Electrochromic cathode materials

ABSTRACT

Various embodiments herein relate to electrochromic devices and electrochromic device precursors, as well as methods and apparatus for fabricating such electrochromic devices and electrochromic device precursors. In certain embodiments, the electrochromic device or precursor may include one or more particular materials such as a particular electrochromic material and/or a particular counter electrode material. In various implementations, the electrochromic material includes tungsten molybdenum oxide. In these or other implementation, the counter electrode material may include nickel tungsten oxide, nickel tungsten tantalum oxide, nickel tungsten niobium oxide, nickel tungsten tin oxide, or another material.

INCORPORATION BY REFERENCE

This application is a continuation-in-part of U.S. patent applicationSer. No. 16/384,822, filed Apr. 15, 2019; and this application claimsbenefit of U.S. Provisional Patent Application No. 62/858,943, filedJun. 7, 2019. Both of these applications are incorporated herein byreference in their entireties and for all purposes.

An Application Data Sheet is filed concurrently with this specificationas part of the present application. Each application that the presentapplication claims benefit of or priority to as identified in theconcurrently filed Application Data Sheet is incorporated by referenceherein in its entirety and for all purposes.

BACKGROUND

Electrochromism is a phenomenon in which a material exhibits areversible electrochemically-mediated change in an optical property whenplaced in a different electronic state, typically by being subjected toa voltage change. The optical property is typically one or more ofcolor, transmittance, absorbance, and reflectance. One well knownelectrochromic material is tungsten oxide (WO₃). Tungsten oxide is acathodic electrochromic material in which a coloration transition,transparent to blue, occurs by electrochemical reduction.

Electrochromic materials may be incorporated into, for example, windowsfor residential, commercial, and other uses. The color, transmittance,absorbance, and/or reflectance of such windows may be changed bychanging a feature of the electrochromic material, that is,electrochromic windows are windows that can be darkened or lightenedelectronically. A small voltage applied to an electrochromic device ofthe window will cause them to darken; reversing the voltage causes themto lighten. This capability allows control of the amount of light thatpasses through the windows, and presents an opportunity forelectrochromic windows to be used as energy-saving devices.

While electrochromism was discovered in the 1960s, electrochromicdevices, and particularly electrochromic windows, still unfortunatelysuffer various problems and have not begun to realized their fullcommercial potential despite many recent advances in electrochromictechnology, apparatus and related methods of making and/or usingelectrochromic devices.

The background description provided herein is for the purposes ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

SUMMARY

Certain embodiments herein relate to electrochromic devices andelectrochromic device precursors, as well as methods and apparatus forforming such electrochromic devices and electrochromic deviceprecursors. In various embodiments, the electrochromic device orelectrochromic device precursor includes an electrochromic layer thatincludes an electrochromic material that includes tungsten, molybdenum,and oxygen. This material is generally referred to as tungstenmolybdenum oxide. In certain cases, the tungsten molybdenum oxideelectrochromic material may be paired with a particular counterelectrode material, for example to provide desirable color qualitieswhen the device is in a tinted state. In some cases, the tungstenmolybdenum oxide electrochromic material may be paired with particularcounter electrode materials where an intrinsic ion conducting andelectrically insulating layer is formed after the tungsten molybdenumoxide electrochromic material and counter electrode material in questionare layered in direct contact with each other. In certain cases, aloneor in combination with aforementioned cases, the tungsten molybdenumoxide electrochromic material is part of a layered stack ofelectrochromic materials. In some cases, the layered stack ofelectrochromic materials may be combined with a layered stack of counterelectrode materials, with a conventional ion conductor layer or anintrinsic ion conductor layer formed in situ as described above. Incertain embodiments, a layered stack of the electrochromic material, thecounter electrode materials, or both, may be substituted with a singlelayer which has a graded composition, that is, the composition of thestack varies across the thickness of the stack.

In one aspect of the disclosed embodiments, an electrochromic device oran electrochromic device precursor is provided, including: a firstelectrically conductive layer having a thickness between about 10-500nm; an electrochromic layer including an electrochromic materialincluding tungsten molybdenum oxide having a composition according tothe formula W_(1-x)Mo_(x)O_(y), where x is between about 0.05-0.30 and yis between about 2.5-4.5. The electrochromic layer may have a thicknessbetween about 100-500 nm; a counter electrode layer including a counterelectrode material including nickel tungsten oxide, the counterelectrode layer having a thickness between about 100-500 nm; and asecond electrically conductive layer having a thickness between about100-400 nm, where the electrochromic layer and the counter electrodelayer are positioned between the first electrically conductive layer andthe second electrically conductive layer, and where the electrochromicdevice is all solid state and inorganic.

In some embodiments, the electrochromic layer may be crystalline (e.g.,nanocrystalline, microcrystalline, or a combination thereof). In someembodiments, the electrochromic layer may be amorphous. Heating thedevice during fabrication may impart special properties to theelectrochromic layer, including durability, faster switching andimproved adhesion. In these or other embodiments, the counter electrodematerial may be crystalline (e.g., nanocrystalline, microcrystalline, ora combination thereof). In some embodiments, the counter electrode layermay be amorphous. In certain implementations, the counter electrodematerial includes nickel tungsten tantalum oxide. In certainimplementations, the counter electrode material includes nickel tungstenniobium oxide. In certain implementations, the counter electrodematerial includes nickel tungsten tin oxide.

One or more of the layers of the electrochromic device or electrochromicdevice precursor may be formed through sputtering. In some cases, theelectrochromic layer, the counter electrode layer, and the secondelectrically conductive layer are all formed through sputtering.

In various implementations, the electrochromic device or electrochromicdevice precursor does not include a homogenous layer of ion conducting,electronically insulating material between the electrochromic layer andthe counter electrode layer. In some cases, the electrochromic materialis in physical contact with the counter electrode material. In these orother cases, at least one of the electrochromic layer and the counterelectrode layer may include two or more layers or portions, one of thelayers or portions being superstoichiometric with respect to oxygen. Inone implementation, either (a) the electrochromic layer includes the twoor more layers, the layer that is superstoichiometric with respect tooxygen being in contact with the counter electrode layer, or (b) thecounter electrode layer includes the two or more layers, the layer thatis superstoichiometric with respect to oxygen being in contact with theelectrochromic layer. In another implementation, either (a) theelectrochromic layer includes the two or more portions, the two or moreportions together forming the electrochromic layer as a graded layer,the portion of the electrochromic layer that is superstoichiometric withrespect to oxygen being in contact with the counter electrode layer, or(b) the counter electrode layer includes the two or more portions, thetwo or more portions together forming the counter electrode layer as agraded layer, the portion of the counter electrode layer that issuperstoichiometric with respect to oxygen being in contact with theelectrochromic layer. In some embodiments, the electrochromic device orelectrochromic device precursor further includes a material that is ionconducting and substantially electronically insulating that is formed insitu at an interface between the electrochromic layer and the counterelectrode layer.

In certain implementations, the electrochromic device or electrochromicdevice precursor further includes an ion conducting layer including amaterial selected from the group consisting of: lithium silicate,lithium aluminum silicate, lithium oxide, lithium tungstate, lithiumaluminum borate, lithium borate, lithium zirconium silicate, lithiumniobate, lithium borosilicate, lithium phosphosilicate, lithium nitride,lithium oxynitride, lithium aluminum fluoride, lithium phosphorusoxynitride (LiPON), lithium lanthanum titanate (LLT), lithium tantalumoxide, lithium zirconium oxide, lithium silicon carbon oxynitride(LiSiCON), lithium phosphate, lithium titanium phosphate, lithiumgermanium vanadium oxide, lithium zinc germanium oxide, and combinationsthereof. In some such cases, the ion conducting layer may have athickness between about 5-100 nm. In some embodiments, the ionconducting layer includes a material selected from the group consistingof: lithium silicate, lithium aluminum silicate, lithium zirconiumsilicate, lithium borosilicate, lithium phosphosilicate, lithiumphosphorus oxynitride (LiPON), lithium silicon carbon oxynitride(LiSiCON), and combinations thereof.

In a further aspect of the disclosed embodiments, a method offabricating an electrochromic device or an electrochromic deviceprecursor is provided, the method including: receiving a substrate witha first electrically conductive layer thereon; forming an electrochromiclayer including an electrochromic material including tungsten molybdenumoxide having a composition according to the formula W_(1-x)Mo_(x)O_(y),where x is between about 0.05-0.20 and y is between about 2.5-4.5;forming a counter electrode layer including a counter electrode materialincluding nickel tungsten oxide; and forming a second electricallyconductive layer, where the electrochromic layer and the counterelectrode layer are positioned between the first electrically conductivelayer and the second electrically conductive layer, and where theelectrochromic device is all solid state and inorganic.

In some embodiments, the electrochromic layer may be crystalline (e.g.,nanocrystalline, microcrystalline, or a combination thereof). In someembodiments, the electrochromic layer may be amorphous. In these orother embodiments, the counter electrode layer may be crystalline (e.g.,nanocrystalline, microcrystalline, or a combination thereof). In someembodiments, the counter electrode layer is amorphous. In certainimplementations, the counter electrode material includes nickel tungstentantalum oxide. In certain implementations, the counter electrodematerial includes nickel tungsten niobium oxide. In someimplementations, the counter electrode material includes nickel tungstentin oxide.

One or more of the layers may be formed through sputtering. For example,in some cases the electrochromic layer, the counter electrode layer, andthe second electrically conductive layer are all formed throughsputtering.

In some cases, the electrochromic device or electrochromic deviceprecursor does not include a homogeneous layer of ion conducting,electronically insulating material between the electrochromic layer andthe counter electrode layer. In some such cases, the electrochromicmaterial may be in physical contact with the counter electrode material.In these or other cases, at least one of the electrochromic layer andthe counter electrode layer may include two or more layers or portions,one of the layers or portions being superstoichiometric with respect tooxygen. For instance, in one example either: (a) the electrochromiclayer includes the two or more layers, the layer that issuperstoichiometric with respect to oxygen being in contact with thecounter electrode layer, or (b) the counter electrode layer includes thetwo or more layers, the layer that is superstoichiometric with respectto oxygen being in contact with the electrochromic layer. In anotherexample, either: (a) the electrochromic layer includes the two or moreportions, the portion of the electrochromic layer that issuperstoichiometric with respect to oxygen being in contact with thecounter electrode layer, or (b) the counter electrode layer includes thetwo or more portions, the portion of the counter electrode layer that issuperstoichiometric with respect to oxygen being in contact with theelectrochromic layer.

In some embodiments the method may further include forming in situ anion conducting layer including a material that is ionically conductiveand substantially electronically insulating, the ion conducting layerbeing positioned at an interface between the electrochromic layer andthe counter electrode layer. In some embodiments, the method may furtherinclude forming an ion conducting layer including a material selectedfrom the group consisting of: lithium silicate, lithium aluminumsilicate, lithium oxide, lithium tungstate, lithium aluminum borate,lithium borate, lithium zirconium silicate, lithium niobate, lithiumborosilicate, lithium phosphosilicate, lithium nitride, lithiumoxynitride, lithium aluminum fluoride, lithium phosphorus oxynitride(LiPON), lithium lanthanum titanate (LLT), lithium tantalum oxide,lithium zirconium oxide, lithium silicon carbon oxynitride (LiSiCON),lithium phosphate, lithium titanium phosphate, lithium germaniumvanadium oxide, lithium zinc germanium oxide, and combinations thereof,wherein the ion conducting layer is formed before forming at least oneof the electrochromic layer and counter electrode layer. In these orother cases, the ion conducting layer may have a thickness between about5-100 nm. In certain cases, the ion conducting layer may include amaterial selected from the group consisting of: lithium silicate,lithium aluminum silicate, lithium zirconium silicate, lithiumborosilicate, lithium phosphosilicate, lithium phosphorus oxynitride(LiPON), lithium silicon carbon oxynitride (LiSiCON), and combinationsthereof.

In certain implementations, the electrochromic layer may be formed bysputtering using one or more metal-containing targets and a firstsputter gas including between about 40-80% O₂ and between about 20-60%Ar, where the substrate is heated, at least intermittently, to betweenabout 150-450° C. during formation of the electrochromic layer, theelectrochromic layer having a thickness between about 200-700 nm, andthe counter electrode layer is formed by sputtering using one or moremetal-containing targets and a second sputter gas including betweenabout 30-100% O₂ and between about 0-30% Ar, the counter electrode layerhaving a thickness between about 100-400 nm. The method may include,after forming the counter electrode layer: heating the substrate in aninert atmosphere at a temperature between about 150-450° C. for aduration between about 10-30 minutes; after heating the substrate in theinert atmosphere, heating the substrate in an oxygen atmosphere at atemperature between about 150-450° C. for a duration between about 1-15minutes; and after heating the substrate in the oxygen atmosphere,heating the substrate in air at a temperature between about 250-350° C.for a duration between about 20-40 minutes. In various embodiments, thesubstrate may be maintained in a vertical orientation during formationof the electrochromic layer, the counter electrode layer, and the secondelectrically conductive layer.

These and other features will be described below with reference to theassociated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a view of an electrochromic device according to certainimplementations.

FIG. 2A is a flowchart of a process flow describing aspects of a methodof fabricating an electrochromic device, according to embodiments.

FIG. 2B are top views depicting steps in the process flow described inrelation to FIG. 2A.

FIG. 2C depicts cross-sections of the electrochromic lite described inrelation to FIG. 2B.

FIG. 2D is a flowchart that describes a method of depositing anelectrochromic stack on a substrate.

FIG. 3A depicts an integrated deposition system according to certainembodiments.

FIG. 3B depicts an integrated deposition system in a perspective view.

FIG. 3C depicts a modular integrated deposition system.

FIG. 3D depicts an integrated deposition system with two lithiumdeposition stations.

FIG. 3E depicts an integrated deposition system with one lithiumdeposition station.

FIG. 4 depicts an example of an electrochromic stack having a cathodicelectrochromic layer that includes two sublayers

FIG. 5 depicts an additional example of an electrochromic stack havinganodic electrochromic layer that includes multiple sublayers.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the presented embodiments.The disclosed embodiments may be practiced without some or all of thesespecific details. In other instances, well-known process operations havenot been described in detail to not unnecessarily obscure the disclosedembodiments. While the disclosed embodiments will be described inconjunction with the specific details, it will be understood that it isnot intended to limit the disclosed embodiments.

Various embodiments herein relate to electrochromic devices,electrochromic device precursors, and methods and apparatus for formingsuch electrochromic devices and electrochromic device precursors. Inmany embodiments, the electrochromic device includes an electrochromicmaterial having a particular composition including at least tungsten,molybdenum, and oxygen. The amount of oxygen in the material will varyaccording to the stoichiometry of the metals in the composition, but maybe defined more specifically as described below.

I. Overview of Electrochromic Devices

A schematic cross-section of an electrochromic device 100 in accordancewith some embodiments is shown in FIG. 1. The electrochromic deviceincludes a substrate 102, a conductive layer (CL) 104, an electrochromiclayer (EC) 106, an ion conducting layer (IC) 108, a counter electrodelayer (CE) 110, and a conductive layer (CL) 114. Elements 104, 106, 108,110, and 114 are collectively referred to as an electrochromic stack120. In some cases, the ion conductor layer 108 may be omitted, asdiscussed further below. A voltage source 116 operable to apply anelectric potential across the electrochromic stack 120 effects thetransition of the electrochromic device from, e.g., a bleached state toa colored state. In other embodiments, the order of layers is reversedwith respect to the substrate. That is, the layers are in the followingorder: substrate, conductive layer, counter electrode layer, ionconducting layer, electrochromic material layer, conductive layer.

Electrochromic layer 106 is cathodically coloring, while the counterelectrode layer 110 may be anodically coloring or optically passive(sometimes referred to as an “ion storage layer” because ions residethere when the device is not tinted). For example, while tungsten oxidecathodically colors to an intense blue shade, nickel oxide anodicallycolors to a brown hue. When colored in tandem, a more neutral blue coloris created. Still, improvements are needed. The inventors havediscovered that certain material changes to tungsten oxide cathodicmaterials, when colored in tandem with certain nickel oxide based anodicmaterials, make for a more aesthetically pleasing hue for electrochromicwindows.

It should be understood that the reference to a transition between ableached state and colored state is non-limiting and suggests only oneexample, among many, of an electrochromic transition that may beimplemented. Unless otherwise specified herein, whenever reference ismade to a bleached-colored transition, the corresponding device orprocess encompasses other optical state transitions suchnon-reflective-reflective, transparent-opaque, etc. Further the term“bleached” refers to an optically neutral state, e.g., uncolored,transparent or translucent. Still further, unless specified otherwiseherein, the “color” of an electrochromic transition is not limited toany particular wavelength or range of wavelengths. As understood bythose of skill in the art, the choice of appropriate electrochromic andcounter electrode materials governs the relevant optical transition.

In certain embodiments, the electrochromic device reversibly cyclesbetween a bleached state and a colored state. In the bleached state, apotential is applied to the electrochromic stack 120 such that availableions in the stack that can cause the electrochromic material 106 to bein the colored state reside primarily in the counter electrode 110. Whenthe potential on the electrochromic stack is reversed, the ions aretransported across the ion conducting layer 108 to the electrochromicmaterial 106 and cause the material to enter the colored state.

In certain embodiments, all of the materials making up electrochromicstack 120 are inorganic, solid (i.e., in the solid state), or bothinorganic and solid. Because organic materials tend to degrade overtime, inorganic materials offer the advantage of a reliableelectrochromic stack that can function for extended periods of time.Materials in the solid state also offer the advantage of not havingcontainment and leakage issues, as materials in the liquid state oftendo. Each of the layers in the electrochromic device is discussed indetail, below. It should be understood that any one or more of thelayers in the stack may contain some amount of organic material, but inmany implementations one or more of the layers contains little or noorganic matter. The same can be said for liquids that may be present inone or more layers in small amounts. It should also be understood thatsolid state material may be deposited or otherwise formed by processesemploying liquid components such as certain processes employing sol-gelsor chemical vapor deposition.

Referring again to FIG. 1, voltage source 116 is typically a low voltageelectrical source (on the order of between about 1V and about 20V,depending upon the electrochromic device used) and may be configured tooperate in conjunction with radiant and other environmental sensors.Voltage source 116 may also be configured to interface with an energymanagement system, such as a computer system that controls theelectrochromic device according to factors such as the time of year,time of day, and measured environmental conditions. Such an energymanagement system, in conjunction with large area electrochromic devices(i.e., an electrochromic window), can dramatically lower the energyconsumption of a building.

A. Substrate

Any material having suitable optical, electrical, thermal, andmechanical properties may be used as substrate 102 in FIG. 1. Suchsubstrates include, for example, glass, plastic, and mirror materials.

In some embodiments, the substrate includes a glass such as a soda limeglass. A substrate may include one or more optional optical tuningand/or ion diffusion barrier layers. Examples of these include silica,titanium dioxide, and undoped tin oxide. Each of an optical tuningand/or ion diffusion barrier layer may have a thickness of about 1-100nm. In one embodiment, an optical tuning and/or an ion diffusion barrierlayer may have a thickness of about 5-50 nm, or 5-30 nm One or more suchlayers may be employed. In some embodiments, such layers include atleast a silica layer and an undoped tin oxide layer. In someembodiments, such layers include at least two separated silica layers.Further examples of such layers are provided in U.S. Pat. No. 5,168,003,which is incorporated herein by reference in its entirety.

The substrate may be of any thickness, as long as it has suitablemechanical properties to support the electrochromic stack 120. While thesubstrate 102 may be of any thickness or transparent material, in someembodiments, it is glass or plastic and is between about 0.01 mm andabout 10 mm thick. In certain embodiments the substrate is glass that isbetween about 3 mm to 9 mm thick, and may be tempered. In otherembodiments, the glass may be very thin, between about 0.01 mm and 1 mmthick, or between about 0.1 mm and 1 mm thick, and be sodium-free orhave very low sodium or other alkali content, e.g., substrates such asCorning, Incorporated's (of Corning, N.Y.) Gorilla®, Willow®, EagleXG®,or other similar glass substrates from commercial sources, such as thosefrom Asahi Glass Corporation (AGC, of Tokyo, Japan).

In some embodiments of the invention, the substrate is architecturalglass. Architectural glass is glass that is used as a building material.Architectural glass is typically used in commercial buildings, but mayalso be used in residential buildings, and typically, though notnecessarily, separates an indoor environment from an outdoorenvironment. In certain embodiments, architectural glass is at least 20inches by 20 inches, and can be much larger, e.g., as large as about 72inches by 120 inches. Architectural glass is typically at least about 2mm thick.

B. Conductive Layers

Returning to FIG. 1, on top of substrate 102 is conductive layer 104. Incertain embodiments, one or both of the conductive layers 104 and 114 isinorganic and/or solid state. Conductive layers 104 and 114 may be madefrom a number of different materials, including conductive oxides, thinmetallic coatings, conductive metal nitrides, and composite conductorsof metal oxides and metals. In certain embodiments, the first conductivelayer, closest to the substrate, is a metallic layer while the secondconducting layer is a transparent metal oxide. Such constructs areuseful for electrochromic mirrors, where incoming light is reflected offthe first conductive layer and must pass through the electrochromicmaterials, and thus a dimming mirror is achieved. Typically, conductivelayers 104 and 114 are transparent at least in the range of wavelengthswhere electrochromism is exhibited by the electrochromic layer and/orsubstantially over the range of the visible spectrum. Transparentconductive oxides include metal oxides and metal oxides doped with oneor more metals. Examples of such metal oxides and doped metal oxidesinclude indium oxide, indium tin oxide, doped indium oxide, tin oxide,doped tin oxide, fluorinated tin oxide, zinc oxide, aluminum zinc oxide,doped zinc oxide, ruthenium oxide, doped ruthenium oxide and the like.Since oxides are often used for these layers, they are sometimesreferred to as “transparent conductive oxide” (TCO) layers. Thinmetallic coatings that are substantially transparent may also be used.Examples of metals used for such thin metallic coatings includetransition metals including gold, platinum, silver, aluminum, nickelalloy, and the like. Thin metallic coatings based on silver, well knownin the glazing industry, are also used. Examples of conductive nitridesinclude titanium nitrides, tantalum nitrides, titanium oxynitrides, andtantalum oxynitrides. The conductive layers 104 and 114 may also becomposite conductors. Such composite conductors may be fabricated byplacing highly conductive ceramic and metal wires or conductive layerpatterns on one of the faces of the substrate and then over-coating withtransparent conductive materials such as doped tin oxides or indium tinoxide. Ideally, such wires should be thin enough as to be invisible tothe naked eye (e.g., about 100 μm or thinner). Other compositeconductors include metal oxide-metal-metal oxide sandwiched materials,such as indium tin oxide-metal-indium tin oxide layers, sometimesgenerically referred to as “IMI's,” where the metal is e.g., silver,gold, copper, aluminum or alloys thereof.

In some embodiments, commercially available substrates such as glasssubstrates contain a transparent conductive layer coating. Such productsmay be used for both substrate 102 and conductive layer 104. Examples ofsuch glasses include conductive layer coated glasses sold under thetrademark TEC Glass™ by Pilkington, of Toledo, Ohio and SUNGATE™ 300 andSUNGATE™ 500 by PPG Industries of Pittsburgh, Pa. TEC Glass™ is a glasscoated with a fluorinated tin oxide conductive layer.

In some embodiments of the invention, the same conductive layer is usedfor both conductive layers (i.e., conductive layers 104 and 114). Insome embodiments, different conductive materials are used for eachconductive layer 104 and 114. For example, in some embodiments, TECGlass™ is used for substrate 102 (float glass) and conductive layer 104(fluorinated tin oxide) and indium tin oxide is used for conductivelayer 114. As noted above, in some embodiments employing TEC Glass™there is a sodium diffusion barrier between the glass substrate 102 andTEC conductive layer 104. In some embodiments, conductive layer 104 hasa layer of titanium dioxide on it, opposite the side abutting thesubstrate. In certain embodiments, the layer of titanium dioxide has athickness of about 50 nm or less. The optional titanium dioxide layermay be employed for its optical and/or insulating properties. Examplesof stacks employing titanium dioxide layers are provided in US PatentApplication Publication No. 2014/0022621, published Jan. 23, 2014, whichis incorporated herein by reference in its entirety.

The function of the conductive layers is to spread an electric potentialprovided by voltage source 116 over surfaces of the electrochromic stack120 to interior regions of the stack, with very little ohmic potentialdrop. The electric potential is transferred to the conductive layersthough electrical connections to the conductive layers. In someembodiments, bus bars, one in contact with conductive layer 104 and onein contact with conductive layer 114, provide the electric connectionbetween the voltage source 116 and the conductive layers 104 and 114.The conductive layers 104 and 114 may also be connected to the voltagesource 116 with other conventional means.

The two conductive layers may be resistance matched, even in cases wherethey are composed of different materials. Resistance matching avoidscases where one conductive layer becomes a tinting bottleneck, as theconductive layer with higher resistance limits tinting time. Also, insuch instances uneven tinting fronts can be an issue.

In some embodiments, the thickness of conductive layers 104 and 114 isbetween about 5 nm and about 10,000 nm. In some embodiments, thethickness of conductive layers 104 and 114 are between about 10 nm andabout 1,000 nm. In other embodiments, the thickness of conductive layers104 and 114 are between about 10 nm and about 500 nm. In someembodiments where TEC Glass™ is used for substrate 102 and conductivelayer 104, the conductive layer is about 300 to 400 nm thick. In someembodiments where indium tin oxide is used for conductive layer 114, theconductive layer is about 100 nm to 500 nm thick (280 nm in oneembodiment). More generally, thicker layers of the conductive materialmay be employed so long as they provide the necessary electricalproperties (e.g., conductivity) and optical properties (e.g.,transmittance). Generally, the conductive layers 104 and 114 are as thinas possible to increase transparency and to reduce cost. In someembodiments, one or both conductive layers are crystalline orsubstantially crystalline. In some embodiment, conductive layers arecrystalline with a high fraction of large equiaxed grains.

The sheet resistance (R_(s)) of the conductive layers is also importantbecause of the relatively large area spanned by the layers in largeelectrochromic windows. In some embodiments, the sheet resistance ofconductive layers 104 and 114 is about 5 to 30 Ohms per square. In someembodiments, the sheet resistance of conductive layers 104 and 114 isabout 15 Ohms per square. In general, it is desirable that the sheetresistance of each of the two conductive layers be about the same. Inone embodiment, the two layers each have a sheet resistance of about10-15 Ohms per square. In one embodiment, the two layers each have asheet resistance of less than 10 Ohms per square or less than 5 Ohms persquare or less than 3 Ohms per square.

C. Electrochromic Layer

Returning to FIG. 1, overlaying conductive layer 104 is electrochromiclayer 106. In embodiments of the invention, electrochromic layer 106 isinorganic and/or solid, in typical embodiments inorganic and solid. Anumber of different materials can be used for the electrochromic layer106. In conventional electrochromic devices, the electrochromic layermay contain e.g., tungsten oxide. The inventors have found thatelectrochromic devices that use tungsten molybdenum oxides in theelectrochromic layer, as described herein, possess improved propertiesover conventional devices. Electrochromic metal oxides may furtherinclude protons, lithium, sodium, potassium, or other ions. Anelectrochromic layer 106 as described herein is capable of receivingsuch ions transferred from counter electrode layer 110.

Tungsten oxide has long been used as an electrochromic material. Overtime, various materials have been added to tungsten oxide to adjust itsproperties. In various embodiments herein, the electrochromic layer 106includes an electrochromic material that includes tungsten, molybdenum,and oxygen. This material may be referred to as tungsten molybdenumoxide. Tungsten molybdenum oxide exhibits both a high degree ofdurability and improved color properties over conventional devices,particularly when used in combination with certain nickel oxide basedcounter electrode materials, such as nickel oxide that contains one ormore of tungsten oxide, tantalum oxide, niobium oxide, tin oxide andmixtures thereof.

The inclusion of molybdenum in the electrochromic material changes thecolor properties of the electrochromic layer, resulting in anelectrochromic device that is more color neutral. Tungsten oxide, forexample, has an intense blue appearance that can be undesirable. Thisblue color is made more neutral with the inclusion of molybdenum.

The tungsten molybdenum oxide materials used in electrochromic devicesdescribed herein may be represented by the formula: W_(1-x)Mo_(x)O_(y),where the total amount of tungsten and molybdenum in the material isrepresented in relative atomic percentage where x is the atomicpercentage of molybdenum and 1-x represents the atomic percentage oftungsten. For example, a compound represented by W_(0.90)Mo_(0.10)O_(y),has a metal content that is 90% (atomic) tungsten, and 10% (atomic) ofmolybdenum.

Of course, the actual material contains oxygen as well as the twometals. For the material, y represents the stoichiometry of the oxygenin the compound relative to, collectively, the metals. In certainembodiments, y is between about 2.5 and about 4.5. In one embodiment, yis between about 3.0 and about 3.5. In one embodiment, y is betweenabout 3.0 and about 3.2. The value of y can have a strong effect on theproperties of the material. Such properties may include whether or notthe material exhibits electrochromism and whether or not the materialcan function as a precursor to an ion conducting material. That is, justas electrochromic tungsten oxide, represented by WO_(y), may have anoxygen content where y is 3 or less, typically between about 2.5 and 3,and superstoichiometric tungsten oxide (which is superstoichiometricwith respect to oxygen and may act as a precursor to an ion conductingmaterial), represented by WO_(y), has an oxygen content where y isgreater than 3, for example between 3.1 and 4.5; the tungsten andmolybdenum in the compounds described herein, collectively, may have thesame associated amounts of oxygen. For example, the material may have 3or less oxygen atoms per metal atom for tungsten molybdenum oxide thatexhibits electrochromism, or more than 3 oxygen atoms per metal atom fortungsten molybdenum oxide that is superstoichiometric with respect tooxygen (and which may act as a precursor to an ion conducting material).Thus, when y is 3 or less, representing a stoichiometric orsubstoichiometric oxygen level for the combined two metals in thematerial, the material is cathodically coloring. Notably, theelectrochromic tungsten molybdenum oxide is more color neutral thane.g., electrochromic tungsten oxide, which has an intense and deep bluecolor when tinted (e.g., via insertion of positive ions such as protonsor lithium ions, and electrons). In certain embodiments, when y is 3 orgreater, the material is superstoichiometrically oxygenated, e.g., whenused in methods of manufacture to fabricate electrochromic devices (andmay be stable as such in an electrochromic device precursor used in theaforementioned methods of manufacture) as described in more detailherein.

For tungsten molybdenum oxide, W_(1-x)Mo_(x)O_(y), the subscripts x andy fall within particular ranges in certain embodiments. For instance, insome embodiments x may be at least about 0.05, or at least about 0.10,or at least about 0.15. In these or other cases, x may be about 0.30 orless, or about 0.25 or less, or about 0.2 or less. In someimplementations, x is about 0.05 and 0.30, or between about 0.10 and0.25, or between about 0.15 and 0.2. In these or other implementations,y may be between about 2.5-4.5, or between about 2.5-3.0, or betweenabout 2.5-2.9, or between about 3.0-3.5, or between about 3.5-4.5. Inthese or other embodiments, y may be at least about 2.5, for example atleast about 2.7, or at least about 2.9, or at least about 3.0, or atleast about 3.5, or at least about 4.0. In these or other cases, y maybe about 4.5 or less, for example about 4.0 or less, or about 3.5 orless, or about 3.3 or less, or about 3.1 or less, or about 3.0 or less,or about 2.9 or less. In certain embodiments, y is about 2.5 to 3.5,about 2.7 to 3.3, about 2.8 to 3.2, or about 2.8 to 3.1.

In some embodiments, the electrochromic material may further includetitanium. For example, the electrochromic material may include tungsten,titanium, molybdenum and oxygen. This material may be referred to astungsten titanium molybdenum oxide. The inclusion of titanium in theelectrochromic material may increase the stability/durability of theelectrochromic layer, meaning that the resulting electrochromic deviceis less likely to break down over time with repeatedinsertion/extraction of ions and electrons.

In various implementations, the electrochromic layer may include two ormore materials (e.g., deposited as a bilayer, graded layer, or othercombination of layers) having different compositions, one or both ofwhich may include tungsten molybdenum oxide. In various embodimentswhere the electrochromic layer includes two or more materials, one ofthe materials may provide electrochromic properties, and the othermaterial may act as a precursor for a material that is ion conductingand substantially electronically insulating.

In certain embodiments, a tungsten oxide portion of an electrochromicstack is deposited in at least two different compositions havingdifferent amounts of oxygen. In one example, the tungsten molybdenumelectrochromic layer is deposited as a bilayer where in a first layer ofthe bilayer, y is between about 2.5 and about 3.5, and in a second layerof the bilayer, y is greater than 3. In another embodiment, the tungstenmolybdenum electrochromic layer is deposited as a single graded layerfabricated such that the value of y varies as a function of the depth ofthe layer. For example, tungsten molybdenum oxide is sputtered onto asubstrate at a first oxygen gas concentration in an initial portion ofthe deposition, then the oxygen gas concentration is increased asadditional tungsten molybdenum oxide material is deposited. Such varyingoxygen concentration between multiple layers or in a graded layer can beused to fabricate ion conductor material in situ, e.g. after a counterelectrode material is deposited and at the interface between thetungsten molybdenum material and the counter electrode material, as isdescribed in more detail below. This fabrication scheme assumes that theelectrochromic layer is formed prior to the counter electrode layer. Incases where the counter electrode layer is formed prior to theelectrochromic layer, the first and second layers of the electrochromiclayer may be swapped (e.g., such that the electrochromic material thatacts as a precursor for the material that is ion conducting andsubstantially electronically insulating is deposited prior to theelectrochromic material that exhibits electrochromism).

In certain cases, the electrochromic layer is deposited in at least twodifferent compositions that have different metals or combinations ofmetals therein. In one example, the electrochromic layer is deposited asa bilayer, where a first layer of the bilayer includes at least onemetal that is not present in the second layer of the bilayer. In theseor other embodiments, the second layer of the bilayer may include atleast one metal that is not present in the first layer of the bilayer.

In one example, the first layer of the bilayer is tungsten molybdenumoxide (e.g., W_(1-x)Mo_(x)O_(y), where y is about 3.5 or less), and thesecond layer of the bilayer is tungsten oxide (e.g., WO_(y), where y isgreater than 3). In another example, the first layer of the bilayer istungsten molybdenum oxide (e.g., W_(1-x)Mo_(x)O_(y), where y is about3.5 or less), and the second layer of the bilayer is tungsten molybdenumoxide (e.g., W_(1-x)Mo_(x)O_(y), where x is between about 0.05 and 0.20,or between about 0.05 and 0.08; and y is greater than 3). In certainother examples, the first and second layers of the bilayer may beswitched, e.g., such that the second layer of the bilayer isW_(1-x)Mo_(x)O_(y) (where y is greater than 3), and the first layer ofthe bilayer is WO_(y) or W_(1-x)Mo_(x)O_(y) (where x is as describedabove with respect to W_(1-x)Mo_(x)O_(y), and where y is about 3.5 orless). For the W_(1-x)Mo_(x)O_(y) materials discussed in this paragraph,the values of x and y may be within the ranges described elsewhereherein.

In embodiments that use a bilayer electrode as described above, eachlayer of the bilayer may have a distinct morphology. In someembodiments, each of the first and second layers of the bilayer has amorphology comprising a microcrystalline phase, a nanocrystalline phase,or an amorphous phase, where each of the first and second layers'morphology is distinct. For example, the first layer of the bilayer istungsten molybdenum oxide (e.g., W_(1-x)Mo_(x)O_(y), where y is about3.5 or less) that is amorphous, and the second layer of the bilayer istungsten oxide (e.g., WO_(y), where y is greater than 3) that isnanocrystalline. In certain embodiments, the first layer of the bilayeris crystalline tungsten molybdenum oxide (e.g., W_(1-x)Mo_(x)O_(y),where y is about 3.5 or less), and the second layer of the bilayer isamorphous tungsten oxide (e.g., WO_(y), where y is greater than 3).Different morphologies for the layers may be chosen for specificpurposes or result from the specific process conditions and/or materialsused for each layer.

The counter electrode layer, discussed further below, may similarly bedeposited as a bilayer or graded layer that includes two or morematerials that may have different compositions with respect to oxygencontent, metal content, etc.

In a number of embodiments, the tungsten molybdenum oxide may have amolybdenum content of at least about 5% (atomic), at least about 6%(atomic), at least about 8% (atomic), or at least about 9% (atomic), orat least about 10% (atomic), or at least about 12% (atomic), or at leastabout 15% (atomic). In these or other cases, the tungsten molybdenumoxide may have a molybdenum content of about 30% (atomic) or less, forexample about 25% (atomic) or less, or about 20% (atomic) or less, orabout 18% (atomic) or less. In a particular example, the tungstenmolybdenum oxide is between about 5-30% (atomic), or about 10-25%(atomic), or about 15-20% (atomic), molybdenum.

In certain embodiments, the tungsten molybdenum oxide electrochromicmaterial is crystalline, nanocrystalline, or amorphous. In someembodiments, the electrochromic material is substantiallynanocrystalline, with grain sizes, on average, from about 5 nm to 50 nm(or from about 5 nm to 20 nm), as characterized by transmission electronmicroscopy (TEM). The electrochromic material morphology may also becharacterized as nanocrystalline using x-ray diffraction (XRD); XRD. Forexample, nanocrystalline electrochromic material may be characterized bythe following XRD features: a crystal size of about 10 to 100 nm (e.g.,about 55 nm. Further, nanocrystalline electrochromic material mayexhibit limited long range order, e.g., on the order of several (about 5to 20) electrochromic material unit cells. In some embodiments, thetungsten molybdenum oxide electrochromic material may be amorphous. Anumber of factors may affect the morphology of the electrochromicmaterial, including, for example, the composition of the material andthe conditions used to deposit and treat the material. In someembodiments, the electrochromic material is not subjected to heatingabove a particular temperature (e.g., any processing involving heatingthe substrate during or after deposition of the electrochromic materialmay be kept below about 300° C., below about 250° C., below about 200°C., below about 150° C., below about 100° C., below about 75° C., orbelow about 50° C.). Without wishing to be bound by theory or mechanismof action, this lack of heating may contribute to an amorphousmorphology for the tungsten molybdenum oxide. In some other embodiments,heating the substrate may cause the tungsten molybdenum oxide'smorphology to become crystalline/nanocrystalline. While not wishing tobe bound by theory, it is believed that the content in the tungstenmolybdenum oxide inhibits crystallization, but under the processingconditions described herein, e.g., higher temperatures and combinationof heating under inert atmosphere followed by heating in air, a morecrystalline morphology can be formed.

In embodiments where the electrochromic layer is deposited to includetwo or more different materials, the different materials may eachindependently include microcrystalline, nanocrystalline, and/oramorphous phases. In one example, a first layer or lower portion of theelectrochromic layer is microcrystalline or nanocrystalline and a secondlayer or upper portion of the electrochromic layer is amorphous. Inanother example, the first layer or lower portion of the electrochromiclayer is amorphous and a second layer or upper portion of theelectrochromic layer is microcrystalline or nanocrystalline. In anotherexample, both the first layer/lower portion and the second layer/upperportion of the electrochromic layer are microcrystalline ornanocrystalline. In another example, both the first layer/lower portionand the second layer/upper portion of the electrochromic layer areamorphous.

The thickness of the electrochromic layer 106 depends on theelectrochromic material selected for the electrochromic layer. In someembodiments, the electrochromic layer 106 is about 50 nm to 2,000 nm, orabout 200 nm to 700 nm. In some embodiments, the electrochromic layer isabout 300 nm to about 500 nm. In certain embodiments employing anadditional tungsten oxide layer (e.g., a layer having WO_(y), where y isgreater than 3), the thickness of this additional layer is about 50 to100 nm. In certain embodiments, this additional layer is amorphous.

Generally, in electrochromic materials, the colorization (or change inany optical property—e.g., absorbance, reflectance, and transmittance)of the electrochromic material is caused by reversible ion insertioninto the material (e.g., intercalation) and a corresponding injection ofa charge balancing electron. Typically some fraction of the ionresponsible for the optical transition is irreversibly bound up in theelectrochromic material. As explained below some or all of theirreversibly bound ions are used to compensate “blind charge” in thematerial. In most electrochromic materials, suitable ions includelithium ions (Li⁺) and hydrogen ions (H⁺) (i.e., protons). In somecases, however, other ions will be suitable. These include, for example,deuterium ions (D⁺), sodium ions (Na⁺), potassium ions (K⁺), calciumions (Ca⁺⁺), barium ions (Ba⁺⁺), strontium ions (Sr⁺⁺), and magnesiumions (Mg⁺⁺). In various embodiments described herein, lithium ions areused to produce the electrochromic phenomena.

D. Counter Electrode Layer

Referring again to FIG. 1, in electrochromic stack 120, ion conductinglayer 108 overlays electrochromic layer 106. On top of ion conductinglayer 108 is counter electrode layer 110. In some embodiments, counterelectrode layer 110 is inorganic and/or solid. The counter electrodelayer may comprise one or more of a number of different materials thatare capable of serving as reservoirs of ions when the electrochromicdevice is in the bleached state. During an electrochromic transitioninitiated by, e.g., application of an appropriate electric potential,the counter electrode layer transfers some or all of the ions it holdsto the electrochromic layer, changing the electrochromic layer to thecolored state. Concurrently, for example in the case of nickel oxidebased materials that are electrochromically active, the counterelectrode layer colors with the loss of ions.

In some embodiments, suitable materials for the counter electrodeinclude nickel oxide (NiO), nickel tungsten oxide (NiWO), nickeltungsten tantalum oxide (NiWTaO), nickel vanadium oxide, nickel chromiumoxide, nickel aluminum oxide, nickel manganese oxide, nickel magnesiumoxide, chromium oxide (Cr₂O₃), manganese oxide (MnO₂), Prussian blue,cerium titanium oxide (CeO₂—TiO₂), cerium zirconium oxide (CeO₂—ZrO₂),vanadium oxide (V₂O₅), and mixtures of oxides (e.g., a mixture of Ni₂O₃and WO₃). Doped formulations of the oxides may also be used, withdopants including, e.g., tantalum and tungsten. Particular examples ofcounter electrode materials include nickel tungsten tantalum oxide,nickel tungsten niobium oxide, and nickel tungsten tin oxide. Becausecounter electrode layer 110 contains the ions used to produce theelectrochromic phenomenon in the electrochromic material when theelectrochromic material is in the bleached state, the counter electrodepreferably has high transmittance and a neutral color when it holdssignificant quantities of these ions.

In some embodiments, a nickel-tungsten oxide (NiWO) is used as a counterelectrode material in the counter electrode layer. In certainembodiments, the amount of nickel present in the nickel-tungsten oxidecan be up to about 90% by weight of the nickel-tungsten oxide. In aspecific embodiment, the mass ratio of nickel to tungsten in thenickel-tungsten oxide is between about 4:6 and 6:4 (e.g., about 1:1). Inone embodiment, the NiWO contains about 15% (atomic) Ni to about 60%(atomic) Ni; about 10% (atomic) W to about 40% W (atomic); and about 30%(atomic) O to about 75% (atomic) O. In another embodiment, the NiWOcontains about 30% (atomic) Ni and about 45% (atomic) Ni; about 10%(atomic) W to about 25% (atomic) W; and about 35% (atomic) O to about50% (atomic) O. In one embodiment, the NiWO contains about 42% (atomic)Ni, about 14% (atomic) W, and about 44% (atomic) O.

In some embodiments, nickel tungsten tantalum oxide (NiWTaO) is used asor in a counter electrode material in the counter electrode layer. Thenickel tungsten tantalum oxide may have various compositions when usedas or in a counter electrode material. In certain embodiments,particular balances may be made between the various components of theNiWTaO. For instance, an atomic ratio of Ni:(W+Ta) in the material mayfall between about 1.5:1 and 3:1, for example between about 1.5:1 and2.5:1, or between about 2:1 and 2.5:1. In a particular example theatomic ratio of Ni: (W+Ta) is between about 2:1 and 3:1. The atomicratio of Ni:(W+Ta) relates to the ratio of (i) nickel atoms in thematerial to (ii) the sum of the number of tungsten and tantalum atoms inthe material. The nickel tungsten tantalum oxide material may also havea particular atomic ratio of W:Ta. In certain embodiments, the atomicratio of W:Ta is between about 0.1:1 and 6:1, for example between about0.2:1 and 5:1, or between about 1:1 and 3:1, or between about 1.5:1 and2.5:1, or between about 1.5:1 and 2:1. In some cases the atomic ratio ofW:Ta is between about 0.2:1 and 1:1, or between about 1:1 and 2:1, orbetween about 2:1 and 3:1, or between about 3:1 and 4:1, or betweenabout 4:1 and 5:1. In some implementations, particular atomic ratios ofNi:(W+Ta) and W:Ta are used. All combinations of disclosed Ni:(W+Ta)compositions and disclosed W:Ta compositions are contemplated, thoughonly certain combinations are explicitly listed herein. For instance,the atomic ratio of Ni:(W+Ta) may be between about 1.5:1 and 3:1, wherethe atomic ratio of W:Ta is between about 1.5:1 and 3:1. In anotherexample, the atomic ratio of Ni:(W+Ta) may be between about 1.5:1 and2.5:1, where the atomic ratio of W:Ta is between about 1.5:1 and 2.5:1.In a further example, the atomic ratio of Ni:(W+Ta) may be between about2:1 and 2.5:1, where the atomic ratio of W:Ta is between about 1.5:1 and2:1, or between about 0.2:1 and 1:1, or between about 1:1 and 2:1, orbetween about 4:1 and 5:1.

In some embodiments, nickel tungsten niobium oxide (NiWNbO) is used as acounter electrode material in the counter electrode layer. The nickeltungsten niobium oxide may have various compositions when used as ananodically coloring material. In certain embodiments, particularbalances may be made between the various components of the NiWNbO. Forinstance, an atomic ratio of Ni:(W+Nb) in the material may fall betweenabout 1.5:1 and 3:1, for example between about 1.5:1 and 2.5:1, orbetween about 2:1 and 2.5:1. In a particular example the atomic ratio ofNi:(W+Nb) is between about 2:1 and 3:1. The atomic ratio of Ni:(W+Nb)relates to the ratio of (i) nickel atoms in the material to (ii) the sumof the number of tungsten and niobium atoms in the material. The nickeltungsten niobium oxide material may also have a particular atomic ratioof W:Nb. In certain embodiments, the atomic ratio of W:Nb is betweenabout 0.1:1 and 6:1, for example between about 0.2:1 and 5:1, or betweenabout 1:1 and 3:1, or between about 1.5:1 and 2.5:1, or between about1.5:1 and 2:1. In some cases the atomic ratio of W:Nb is between about0.2:1 and 1:1, or between about 1:1 and 2:1, or between about 2:1 and3:1, or between about 3:1 and 4:1, or between about 4:1 and 5:1. In someimplementations, particular atomic ratios of Ni:(W+Nb) and W:Nb areused. All combinations of disclosed Ni:(W+Nb) compositions and disclosedW:Nb compositions are contemplated, though only certain combinations areexplicitly listed herein. For instance, the atomic ratio of Ni: (W+Nb)may be between about 1.5:1 and 3:1, where the atomic ratio of W:Nb isbetween about 1.5:1 and 3:1. In another example, the atomic ratio ofNi:(W+Nb) may be between about 1.5:1 and 2.5:1, where the atomic ratioof W:Nb is between about 1.5:1 and 2.5:1. In a further example, theatomic ratio of Ni:(W+Nb) may be between about 2:1 and 2.5:1, where theatomic ratio of W:Nb is between about 1.5:1 and 2:1, or between about0.2:1 and 1:1, or between about 1:1 and 2:1, or between about 4:1 and5:1.

In some embodiments, nickel tungsten tin oxide (NiWSnO) is used in thecounter electrode layer. The nickel tungsten tin oxide may have variouscompositions when used as an anodically coloring material. In certainembodiments, particular balances may be made between the variouscomponents of the NiWSnO. For instance, an atomic ratio of Ni:(W+Sn) inthe material may fall between about 1:1 and 4:1, for example betweenabout 1:1 and 3:1, or between about 1.5:1 and 3:1 , or between about1.5:1 and 2.5:1, or between about 2:1 and 2.5:1. In a particular examplethe atomic ratio of Ni:(W+Sn) is between about 2:1 and 3:1. The atomicratio of Ni:(W+Sn) relates to the ratio of (i) nickel atoms in thematerial to (ii) the sum of the number of tungsten and tin atoms in thematerial. The nickel tungsten tin oxide material may also have aparticular atomic ratio of W:Sn. In certain embodiments, the atomicratio of W:Sn is between about 1:9 and 9:1, for example between about1:1 and 3:1, or between about 1.5:1 and 2.5:1, or between about 1.5:1and 2:1. In some implementations, particular atomic ratios of Ni:(W+Sn)and W:Sn are used. For instance, the atomic ratio of Ni:(W+Sn) may bebetween about 1:1 and 3:1, where the atomic ratio of W:Sn is betweenabout 1:1 and 3:1. In another example, the atomic ratio of Ni:(W+Sn) maybe between about 1.5:1 and 2.5:1, where the atomic ratio of W:Sn isbetween about 1.5:1 and 2.5:1. In a further example, the atomic ratio ofNi:(W+Sn) may be between about 2:1 and 2.5:1, where the atomic ratio ofW:Sn is between about 1.5:1 and 2:1.

When charge is removed from a counter electrode 110 made of nickeltungsten oxide (i.e., ions are transported from the counter electrode110 to the electrochromic layer 106), the counter electrode layer willturn from a transparent state to a brown colored state. Otherelectrochromically active counter electrode materials may exhibitsimilar or other colors upon ion removal.

As discussed above with respect to the electrochromic layer, the counterelectrode layer may be deposited to include two or more materials (e.g.,deposited as a bilayer, graded layer, or other combination of layers)having different compositions. In a number of these embodiments, one ofthe counter electrode materials may provide electrochromic properties,and the other counter electrode material may act as a precursor for amaterial that is ion conducting and substantially electronicallyinsulating. Typically, a material that acts as a precursor for amaterial that is ion conducting and substantially electronicallyinsulating, when present, will be formed in contact with theelectrochromic material. In cases where the electrochromic layer isformed prior to the counter electrode layer, the counter electrodematerial that acts as a precursor to the ion conducting andsubstantially electronically insulating material may be deposited as afirst layer or lower portion of the counter electrode layer. The counterelectrode material that exhibits electrochromism may then be provided asthe second layer or upper portion of the counter electrode layer. Incases where the counter electrode layer is deposited prior to theelectrochromic layer, the first layer or lower portion of the counterelectrode may be formed of the counter electrode material that exhibitselectrochromism, and the second layer or upper portion of the counterelectrode may be formed of the counter electrode material that acts as aprecursor for the material that is ion conducting and substantiallyelectronically insulating.

In one example, the counter electrode is deposited to include twomaterials that have different oxygen contents. For instance, the counterelectrode layer may include two different forms of nickel oxide, or twodifferent forms of nickel tungsten oxide, or two different forms ofnickel tungsten tantalum oxide, or two different forms of nickeltungsten niobium oxide, or two different forms of nickel tungsten tinoxide, etc., where the two different forms of the counter electrodematerial have different oxygen concentrations. One form of the counterelectrode material may exhibit electrochromism, and may have relativelyless oxygen. The other form of the counter electrode material may or maynot exhibit electrochromism, may act as a precursor for a material thatis ion conducting and substantially electronically insulating, and mayhave relatively more oxygen. The counter electrode material that hasrelatively more oxygen and acts as a precursor for the ion conductingand substantially electronically insulating material may besuperstoichiometric with respect to oxygen. Details provided hereinregarding differences in oxygen content between different layers orportions of the electrochromic or counter electrode layers may applyregardless of whether there are other compositional differences (e.g.,different metals) between the two layers or portions in question.

In certain embodiments, the counter electrode may be deposited toinclude two or more materials that have different metal compositions,optionally in different layers disposed closer to and farther from theelectrochromic layer. For example, a first counter electrode material(in a layer closer to the electrochromic layer) may include one or moremetal that is not present in the second counter electrode material.Likewise, the second counter electrode material may include one or moremetal that is not present in the first counter electrode material.Example first counter electrode materials include, but are not limitedto, nickel oxide, nickel tungsten oxide, nickel tungsten tantalum oxide,nickel tungsten tin oxide, and nickel tungsten niobium oxide. Examplesecond counter electrode materials likewise include, but are not limitedto, nickel oxide, nickel tungsten oxide, nickel tungsten tantalum oxide,nickel tungsten tin oxide, and nickel tungsten niobium oxide. A fewexample combinations are provided, but are not intended to be limiting.In one example, the first counter electrode material (in a layer closerto the electrochromic layer) is nickel tungsten oxide and the secondcounter electrode material is nickel oxide. In another example, thefirst counter electrode material is nickel tungsten tantalum oxide andthe second counter electrode material is nickel tungsten oxide. Inanother example, the first counter electrode material is nickel tungstentin oxide and the second counter electrode material is nickel tungstenoxide. In another example, the first counter electrode material isnickel tungsten niobium oxide and the second counter electrode materialis nickel tungsten oxide. In another example, the first counterelectrode material (in a layer closer to the electrochromic layer) isnickel tungsten oxide, and the second counter electrode materials isnickel tungsten tantalum oxide. Any of these examples can be modified toinclude different first/second counter electrode materials.

The counter electrode morphology may be crystalline, amorphous, or somemixture thereof. Crystalline phases may be nanocrystalline. In someembodiments, the counter electrode material is amorphous orsubstantially amorphous. Various substantially amorphous counterelectrodes have been found to perform better, under some conditions, incomparison to their crystalline counterparts. The amorphous state of thecounter electrode oxide material may be obtained through the use ofcertain processing conditions, described below. While not wishing to bebound to any theory or mechanism, it is believed that certain amorphouscounter electrode oxides are produced by relatively low energy atoms inthe sputtering process. Low energy atoms are obtained, for example, in asputtering process with lower target powers, higher chamber pressures(i.e., lower vacuum), and/or larger source to substrate distances.Amorphous films are also more likely to form where there is a relativelyhigher fraction/concentration of heavy atoms (e.g., W). Under thedescribed process conditions, films with better stability under UV/heatexposure are produced. Substantially amorphous materials may have somecrystalline, typically but not necessarily nanocrystalline, materialdispersed in the amorphous matrix.

In embodiments where the counter electrode is deposited to include twoor more different materials, the different materials may eachindependently include microcrystalline, nanocrystalline, and/oramorphous phases. In one example, a first layer or lower portion of thecounter electrode layer is microcrystalline or nanocrystalline and asecond layer or upper portion of the counter electrode layer isamorphous. In another example, the first layer or lower portion of thecounter electrode layer is amorphous and a second layer or upper portionof the counter electrode layer is microcrystalline or nanocrystalline.In another example, both the first layer/lower portion and the secondlayer/upper portion of the counter electrode layer are microcrystallineor nanocrystalline. In another example, both the first layer/lowerportion and the second layer/upper portion of the counter electrodelayer are amorphous.

In some embodiments, the counter electrode morphology may includemicrocrystalline, nanocrystalline and/or amorphous phases. For example,the counter electrode may be, e.g., a material with an amorphous matrixhaving nanocrystals distributed throughout. In certain embodiments, thenanocrystals constitute about 50% or less of the counter electrodematerial, about 40% or less of the counter electrode material, about 30%or less of the counter electrode material, about 20% or less of thecounter electrode material or about 10% or less of the counter electrodematerial (by weight or by volume depending on the embodiment). Incertain embodiments, the nanocrystals have a maximum diameter of lessthan about 50 nm, in some cases less than about 25 nm, less than about10 nm, or less than about 5 nm. In some cases, the nanocrystals have amean diameter of about 50 nm or less, or about 10 nm or less, or about 5nm or less (e.g., about 1-10 nm).

In certain embodiments, it is desirable to have a nanocrystal sizedistribution where at least about 50% of the nanocrystals have adiameter within 1 standard deviation of the mean nanocrystal diameter,for example where at least about 75% of the nanocrystals have a diameterwithin 1 standard deviation of the mean nanocrystal diameter or where atleast about 90% of the nanocrystals have a diameter within 1 standarddeviation of the mean nanocrystal diameter.

It has been found that counter electrodes that include an amorphousmatrix may operate more efficiently compared to counter electrodes thatare relatively more crystalline. In certain embodiments, an additive mayform a host matrix in which domains of a base anodically coloringmaterial may be found. In various cases, the host matrix issubstantially amorphous. In certain embodiments, the only crystallinestructures in the counter electrode are formed from a base anodicallycoloring electrochromic material in, e.g., oxide form. One example of abase anodically coloring electrochromic material in oxide form is nickeltungsten oxide. Additives may contribute to forming an amorphous hostmatrix that is not substantially crystalline, but which incorporatesdomains (e.g., nanocrystals in some cases) of the base anodicallycoloring electrochromic material. Example additives include, but are notlimited to, tin, tantalum, and niobium. In other embodiments, theadditive and the anodically coloring base material together form achemical compound with covalent and/or ionic bonding. The compound maybe crystalline, amorphous, or a combination thereof. In otherembodiments, the anodically coloring base material forms a host matrixin which domains of the additive exist as discrete phases or pockets.For example certain embodiments include an amorphous counter electrodehaving an amorphous matrix of a first material, with a second material,also amorphous, distributed throughout the first material in pockets,for example, pockets of the diameters described herein for crystallinematerials distributed throughout an amorphous matrix.

In some embodiments, the thickness of the counter electrode is about 50nm about 650 nm. In some embodiments, the thickness of the counterelectrode is about 100 nm to about 400 nm, preferably in the range ofabout 200 nm to 300 nm.

The amount of ions held in the counter electrode layer during thebleached state (and correspondingly in the electrochromic layer duringthe colored state) and available to drive the electrochromic transitiondepends on the composition of the layers as well as the thickness of thelayers and the fabrication method. Both the electrochromic layer and thecounter electrode layer are capable of supporting available charge (inthe form of lithium ions and electrons) in the neighborhood of severaltens of millicoulombs per square centimeter of layer surface area. Thecharge capacity of an electrochromic film is the amount of charge thatcan be loaded and unloaded reversibly per unit area and unit thicknessof the film by applying an external voltage or potential. In oneembodiment, the electrochromic layer has a charge capacity of betweenabout 30 and about 150 mC/cm²/micron. In another embodiment, theelectrochromic layer has a charge capacity of between about 50 and about100 mC/cm²/micron. In one embodiment, the counter electrode layer has acharge capacity of between about 75 and about 200 mC/cm²/micron. Inanother embodiment, the counter electrode layer has a charge capacity ofbetween about 100 and about 150 mC/cm²/micron.

E. Ion Conducting Layer

In various embodiments such as the one shown in FIG. 1, an ion conductorlayer 108 is provided between the electrochromic layer 106 and thecounter electrode layer 110. In such cases, an ion conductor material isdeposited in a conventional sense, e.g., atop the electrochromic layervia e.g., sputtering, evaporation, sol-gel techniques, and the like,followed by deposition of the counter electrode material. In otherembodiments, a conventional ion conductor layer may be omitted. In suchcases, the electrochromic layer and the counter electrode layer may bedeposited in direct contact with one another, and an ion conductingmaterial formed in situ at the interface between these two layers mayserve the purpose of a conventional ion conductor layer. Electrochromicdevice precursors may include the stack of aforementioned layers priorto the in situ formation of the ion conductor material. Each of theseembodiments will be discussed in turn.

i. Embodiments Utilizing a Separately Deposited Ion Conducting Layer

As shown in FIG. 1, in between electrochromic layer 106 and counterelectrode layer 110, there is an ion conducting layer 108. Ionconducting layer 108 serves as a medium through which ions aretransported (in the manner of an electrolyte) when the electrochromicdevice transforms between the bleached state and the colored state.Preferably, ion conducting layer 108 is highly conductive to therelevant ions for the electrochromic and the counter electrode layers,but has sufficiently low electron conductivity that negligible electrontransfer takes place during normal operation. A thin ion conductinglayer with high ionic conductivity permits fast ion conduction and hencefast switching for high performance electrochromic devices. In certainembodiments, the ion conducting layer 108 is inorganic and/or solid.When fabricated from a material and in a manner that produces relativelyfew defects, the ion conductor layer can be made very thin to produce ahigh performance device. In various implementations, the ion conductormaterial has an ionic conductivity of between about 10⁸ Siemens/cm orohm⁻¹ cm⁻¹ and about 10⁹ Siemens/cm or ohm⁻¹ cm⁻¹ and an electronicresistance of about 10¹¹ ohms-cm.

Examples of suitable materials for the lithium ion conductor layerinclude lithium silicate, lithium aluminum silicate, lithium oxide,lithium tungstate, lithium aluminum borate, lithium borate, lithiumzirconium silicate, lithium niobate, lithium borosilicate, lithiumphosphosilicate, lithium nitride, lithium oxynitride, lithium aluminumfluoride, lithium phosphorus oxynitride (LiPON), lithium lanthanumtitanate (LLT), lithium tantalum oxide, lithium zirconium oxide, lithiumsilicon carbon oxynitride (LiSiCON), lithium titanium phosphate, lithiumgermanium vanadium oxide, lithium zinc germanium oxide, and otherceramic materials that allow lithium ions to pass through them whilehaving a high electrical resistance (blocking electron movementtherethrough). Any material, however, may be used for the ion conductinglayer 108 provided it can be fabricated with low defectivity and itallows for the passage of ions between the counter electrode layer 110to the electrochromic layer 106 while substantially preventing thepassage of electrons.

In certain embodiments, the ion conducting layer is crystalline,nanocrystalline, or amorphous. Typically, the ion conducting layer isamorphous. In another embodiment, the ion conducting layer isnanocrystalline. In yet another embodiment, the ion conducting layer iscrystalline.

In some embodiments, a silicon-aluminum-oxide (SiAlO) is used for theion conducting layer 108. In a specific embodiment, a silicon/aluminumtarget used to fabricate the ion conductor layer via sputtering containsbetween about 6 and about 20 atomic % aluminum. This defines the ratioof silicon to aluminum in the ion conducting layer. In some embodiments,the silicon-aluminum-oxide ion conducting layer 108 is amorphous.

The thickness of the ion conducting layer 108 may vary depending on thematerial. In some embodiments, the ion conducting layer 108 is about 5nm to 100 nm thick, preferably about 10 nm to 60 nm thick. In someembodiments, the ion conducting layer is about 15 nm to 40 nm thick orabout 25 nm to 30 nm thick.

Ions transported across the ion conducting layer between theelectrochromic layer and the counter electrode layer serve to effect acolor change in the electrochromic layer (i.e., change theelectrochromic device from the bleached state to the colored state).Depending on the choice of materials for the electrochromic devicestack, such ions include lithium ions (Li⁺) and hydrogen ions (H⁺)(i.e., protons). As mentioned above, other ions may be employed incertain embodiments. These include deuterium ions (D⁺), sodium ions(Na⁺), potassium ions (K⁺), calcium ions (Ca⁺⁺), barium ions (Ba⁺⁺),strontium ions (Sr⁺⁺), and magnesium ions (Mg⁺⁺).

ii. Embodiments Omitting a Separately Deposited Ion Conducting Layer

In most conventional electrochromic devices, the ion conducting layer isdeposited as a distinct material in a distinct deposition step toprovide separation between the electrochromic layer and the counterelectrode layer. However, in certain embodiments herein, the ionconducting layer may be omitted. In such cases, the electrochromicmaterial of the electrochromic layer may be deposited in direct physicalcontact with the counter electrode material of the counter electrodelayer. An interfacial region between the electrochromic layer and thecounter electrode layer may form and serve the function of an ionconductor layer (e.g., allowing passage of ions but not electronsbetween the electrochromic layer and the counter electrode layer),without the need to ever deposit this layer as a distinct material. Thissimplifies formation of the electrochromic device, since there is noneed to provide a separate deposition step for forming the ion conductorlayer.

In such embodiments, one or both of the electrochromic layer and counterelectrode layer may be deposited to include a portion that isoxygen-rich compared to the remaining portion of the layer. Theoxygen-rich portion may be superstoichiometric with respect to oxygen.Typically, the oxygen-rich portion is in contact with the other type oflayer. For instance, an electrochromic stack may include a counterelectrode material in contact with an electrochromic material, where theelectrochromic material includes an oxygen-rich portion in directphysical contact with the counter electrode material. In anotherexample, an electrochromic stack includes a counter electrode materialin contact with an electrochromic material, where the counter electrodematerial includes an oxygen-rich portion in direct physical contact withthe electrochromic material. In a further example, both theelectrochromic material and the counter electrode material each includean oxygen-rich portion, where the oxygen-rich portion of theelectrochromic material is in direct physical contact with theoxygen-rich portion of the counter electrode material.

The oxygen-rich portions of these materials may be provided as distinctlayers. For instance, an electrochromic and/or counter electrodematerial may include a first layer that is oxygen-rich and a secondlayer that is not oxygen-rich (or has relatively less oxygen incomparison to the first layer). Unless otherwise specified, as usedherein the term “oxygen-rich” refers to a material that issuperstoichiometric with respect to oxygen. Further, a material that is“oxygen-rich” in comparison to a second material has a higher degree ofsuperstoichiometric oxygen compared to the second material. In someexamples, the electrochromic layer includes two layers of tungstenmolybdenum oxide, where a second layer of tungsten molybdenum oxide isoxygen-rich in comparison to the first layer of tungsten molybdenumoxide. The second layer of tungsten molybdenum oxide may besuperstoichiometric with respect to oxygen. The second layer of tungstenmolybdenum oxide may be in direct physical contact with the counterelectrode layer and with the first layer of tungsten molybdenum oxide.The counter electrode layer may be homogeneous, or it may also includean oxygen-rich portion, as noted above.

The oxygen-rich portion of the layers may also be provided in a gradedlayer. For example, the electrochromic and/or counter electrode materialmay include a gradient in oxygen concentration, the gradient being in adirection normal to the surface of the layers. In some examples, theelectrochromic layer is a graded layer of tungsten molybdenum oxide,having a graded oxygen concentration in a direction normal to thesurface of the layer. For instance, the highest oxygen concentration inthe graded tungsten molybdenum oxide layer may be proximate the counterelectrode layer. The counter electrode layer may be homogeneous, or itmay also include an oxygen-rich portion, as noted above.

Embodiments where the ion conductor layer deposition step is omitted andthe counter electrode material is deposited in direct contact with theelectrochromic material are further discussed in the following U.S.Patents, each of which is herein incorporated by reference in itsentirety: U.S. Pat. Nos. 8,300,298, 8,764,950, and 9,261,751.

F. Additional Layers

The electrochromic device 100 may include one or more additional layers(not shown in FIG. 1) such as one or more passive layers. Passive layersused to improve certain optical properties may be included inelectrochromic device 100. Passive layers for providing moisture orscratch resistance may also be included in the electrochromic device100. For example, the conductive layers may be treated withanti-reflective or protective oxide or nitride layers. Other passivelayers may serve to hermetically seal the electrochromic device 100.

In various embodiments, one or more defect mitigating insulating layers(DMILs) may be provided. Such DMILs may be provided between the layersdescribed in FIG. 1, or within such layers. In some particularembodiments a DMIL may be provided between sublayers of a counterelectrode layer, though DMILs can also be provided at alternative oradditional locations. DMILs can help minimize the risk of fabricatingdefective devices. In certain embodiments, the insulating layer has anelectronic resistivity of between about 1 and 5×10¹⁰ Ohm-cm. In certainembodiments, the insulating layer contains one or more of the followingmetal oxides: cerium oxide, titanium oxide, aluminum oxide, zinc oxide,tin oxide, silicon aluminum oxide, tungsten oxide, nickel tungstenoxide, tantalum oxide, and oxidized indium tin oxide. In certainembodiments, the insulating layer contains a nitride, carbide,oxynitride, or oxycarbide such as nitride, carbide, oxynitride, oroxycarbide analogs of the listed oxides. As an example, the insulatinglayer includes one or more of the following metal nitrides: titaniumnitride, aluminum nitride, silicon nitride, and tungsten nitride. Theinsulating layer may also contain a mixture or other combination ofoxide and nitride materials (e.g., a silicon oxynitride). DMILs arefurther described in U.S. Pat. No. 9,007,674, which is hereinincorporated by reference in its entirety.

G. Example Electrochromic Device Stacks Having Cathodic ElectrochromicSublayers

FIG. 4 shows an example of an electrochromic stack having a cathodicelectrochromic layer that includes two sublayers. As illustrated, thestack in FIG. 4 includes transparent conductive oxide layers 404 and414, cathodically coloring electrochromic layer 406, and anodicallycoloring counter electrode layer 410. Here, cathodically coloringelectrochromic layer 406 includes two sublayers 406 a and 406 b. Thefirst sublayer 406 a may include a known electrochromic cathodicallycoloring material such as tungsten oxide or tungsten molybdenum oxide.The second sublayer 406 b may include one or more different elementssuch as a case where sublayer 406 a contains tungsten, molybdenum, andoxygen but sublayer 406 b contains only tungsten and oxygen or viceversa. In another embodiment, sublayers 406 a and 406 b include the sameelements, but at different relative concentrations. For example, bothsublayers may contain tungsten, molybdenum, and oxygen, but sublayer 406a is stoichiometric or substoichiometric in oxygen while sublayer 406 bis superstoichiometric in oxygen. As explained above, in variousembodiments, a second sublayer (e.g., sublayer 406 b) may besuperstoichiometric in oxygen. As an example, sublayer 406 b may beexpressed as WO_(y), where y is greater than 3 or as W_(1-x)Mo_(x)O_(y),where y is greater than 3.In certain embodiments, an IC layer (not shownin FIG. 4) is disposed between the electrochromic layer 406 and thecounter electrode layers 410. In certain embodiments, the secondsublayer 406 b converts, at least partially, to function as an IC layer.

FIG. 5 shows an additional example of an electrochromic stack thatincludes transparent conductive oxide layers 504 and 514, cathodicallycoloring electrochromic layer 606, and anodically coloring counterelectrode layer 511. Here, counter electrode layer 511 includes threesublayers 511 a-c. The first sublayer 511 a may be a flash layer. Eachof the sublayers 511 a-c may have a different composition. Or any two orthree of them may have the same composition. The second and thirdsublayers 511 b and 511 c may include the same elements at differentrelative concentrations in some embodiments. In another embodiment, allof the sublayers 511 a-c include the same elements at different relativeconcentrations. There may be an IC layer (not shown in FIG. 5) betweenthe electrochromic layer 506 and the counter electrode layers 511.

The first sublayer 511 a may be a first anodically coloring counterelectrode material, and the second and third sublayers 511 b and 511 cmay be a second anodically coloring counter electrode material (eachdeposited at a different composition). The composition of the second andthird sublayers 511 b and 511 c may be homogeneous within each sublayer.

In this embodiment, as with the embodiment of FIG. 4, the cathodicallycoloring electrochromic layer 506 includes two sublayers 506 a and 506b. The first sublayer 506 a may include a known electrochromiccathodically coloring material such as tungsten oxide or tungstenmolybdenum oxide. The second sublayer 506 b may include one or moredifferent elements such as a case where sublayer 506 a containstungsten, molybdenum, and oxygen but sublayer 506 b contains onlytungsten and oxygen. In another embodiment, sublayers 506 a and 506 binclude the same elements, but at different relative concentrations. Forexample, both sublayers may contain tungsten, molybdenum, and oxygen,but sublayer 506 a is stoichiometric or substoichiometric in oxygenwhile sublayer 506 b is superstoichiometric in oxygen.

Various examples of multilayer counter electrodes are described in USPatent Application Publication No. 20170003564, filed Jul. 7, 2016,which is incorporated herein by reference in its entirety. As explainedthere, in some implementations, the first counter electrode sublayer isa flash layer, which is generally characterized as a thin and oftenquickly deposited layer typically having a thickness of not greater thanabout 100 nm, in various cases not greater than about 80 nm. A flashlayer may be between about 5 nm thick and about 100 nm thick, betweenabout 10 nm thick and about 80 nm thick, or between about 10 nm thickand about 50 nm thick, or about 10 nm and about 30 nm thick. In someother cases, a separate flash layer (which may be an anodically coloringcounter electrode material) may be provided between the electrochromiclayer and the first sublayer of the counter electrode. In someembodiments, a flash layer may be provided between the second sublayerand the transparent conductor layer. A flash layer, if present, may ormay not exhibit electrochromic properties. In certain embodiments, aflash layer is made of a counter electrode material that does not changecolor with remaining electrochromic/counter electrode layers (thoughthis layer may have a composition that is very similar to other layerssuch as an anodically coloring layer). In some embodiments, the firstsublayer, whether a flash layer or thicker than a flash layer, has arelatively high electronic resistivity, for example between about 1 and5×10¹⁰ Ohm-cm.

In some examples, a third counter electrode is a defect-mitigatinginsulating layer as described elsewhere herein.

In certain embodiments, the electrochromic stack has an optional caplayer that may be disposed between the counter electrode layer (or theelectrochromic layer if it is separated from the substrate by thecounter electrode layer) and the second transparent conductive layer. Incertain embodiments, the cap layer has a composition matching or similarto the counter electrode layer or a sublayer therein. In someimplementations, the cap layer comprises a nickel tungsten oxide, e.g.,NiWO. In certain embodiments, the cap layer is about 0 to 50 nm thick.In some embodiments, the cap layer serves as a defect-mitigatinginsulating layer.

In certain embodiments, the electrochromic stack includes a hermeticlayer over the second conductive layer. As an example, the hermeticlayer may comprise a silicon oxide, a silicon oxynitride, a siliconnitride, a silicon aluminum oxide, an aluminum oxide, an aluminumnitride, an aluminum zinc oxide, a tin oxide, carbon (e.g., graphene,graphite, diamond-like carbon, and/or fluorinated diamond-like carbon),a titanium oxide, a titanium nitride, a tantalum nitride, a tin oxide, azinc oxide, chromium, an organic polymer (e.g., a parylene polymer), andmixtures thereof. In general, any of these materials may have any ofvarious morphologies or crystallinities, including amorphous,crystalline, or mixed amorphous-crystalline. In certain embodiments, ahermetic layer has a thickness of about 50 nm to 5 micrometers, or about100 nm to 3 micrometers, or about 100 nm to 1 micrometer.

Table 1 below presents information for electrochromic device stacks inaccordance with certain embodiments.

Layer Composition Thickness Substrate Substrate (e.g., Sodalime variableglass)    0-100 nm Optical tuning and/or ion diffusion barrier layers(optional) TCO1 TCO (e.g., FTO) ~100-700 nm TiO2 (optional)  ~0-50 nmEC/“Wa” WOx or doped WOx ~200-700 nm IC/“Wb” WOx + b  ~30-200 nm CE NiWOor doped NiWO ~100-500 nm One or more layers (total) Cap (optional) NiWO(example)  ~0-50 nm TCO2 E.g., ITO ~200-700 nm Hermetic seal e.g.silicon nitride, ~0.5-5 μm  (optional) titanium nitride, siliconoxynitride, silicon aluminum oxide, and various carbon materials.

II. Methods of Fabricating Electrochromic Devices and Precursors

Formation of electrochromic devices and electrochromic device precursorsinvolves deposition of a number of different layers on a substrate. Eachof these layers is discussed above. A number of other steps may also betaken when fabricating an electrochromic device or precursor, asdescribed in FIG. 2A, for example.

As used herein, an electrochromic device precursor is a partiallyfabricated electrochromic device which is not yet suitable forfunctioning as a finished electrochromic device. Typically, anelectrochromic device precursor includes at least a first conductivelayer, an electrochromic layer, a counter electrode layer, and a secondconductive layer. Additional layers may be present in some cases. Insome embodiments, an electrochromic device precursor has materialswithin its structure that, although not suitable for function as afinished device, are configured or suited for physical and/or chemicalconversion to become a functioning device. Such device precursors may bedesirable, e.g., in cases where substrates are coated with the precursormaterials, stored or shipped to another facility, for later and/ordownstream processing.

For instance, a separate ion conducting layer may not be present incertain embodiments. In cases where the ion conducting layer is omitted,the electrochromic device precursor may lack any layer or region thatwould serve the purpose of an ion conducting layer (e.g., allowingpassage of ions but not electrons between the electrochromic layer andthe counter electrode layer). An electrochromic device precursor can befurther processed to form an electrochromic device. In cases where theion conducting layer is omitted, this further processing may form amaterial that is ionically conductive and substantially electronicallyinsulating in an interfacial region between the electrochromic layer andthe counter electrode layer. In various embodiments, this furtherprocessing may involve thermal conditioning, as described further below.In certain embodiments, one or both of the electrochromic and counterelectrode material are superstoichiometrically oxygenated at theinterface of the layers, or otherwise an excess of oxygen or otherreactive species is present between the layers. Thesuperstoichiometrically oxygenated material may later be converted tothe material that is ionically conductive and substantiallyelectronically insulating. In these or other embodiments, furtherprocessing may involve lithiation of one or more layers in theelectrochromic device, either through direct lithium deposition orthrough diffusion. For example, the lithium added reacts or otherwisecombines with the oxygen or other reactive species at the interface toform an ion conducting and electronically insulating material at theinterface between the electrochromic and counter electrode materiallayers. In these or other embodiments, this further processing mayinvolve flowing current between electrochromic and counter electrodelayers. Any one or more of these further processing steps may beinvolved in formation of an electrochromic device from an electrochromicdevice precursor in certain implementations.

FIG. 2A is a process flow, 200, describing aspects of a method offabricating an electrochromic device or other optical device havingopposing bus bars, each applied to one of the conductive layers of theoptical device. The dotted lines denote optional steps in the processflow. An exemplary device, 240, as described in relation to FIGS. 2B-C,is used to illustrate the process flow. FIG. 2B provides top viewsdepicting the fabrication of device 240 including numerical indicatorsof process flow 200 as described in relation to FIG. 2A. FIG. 2C showscross-sections of the lite including device 240 described in relation toFIG. 2B. Device 240 is a rectangular device, but process flow 200applies to any shape of optical device having opposing bus bars, each onone of the conductive layers.

Referring to FIGS. 2A and 2B, after receiving a substrate with a firstconductive layer thereon, process flow 200 begins with an optionalpolishing of the first conductive layer, see 201. Polishing, ifperformed, may be done prior to an edge deletion, see 205, and/or afteran edge deletion in the process flow.

Referring again to FIG. 2A, if polishing 201 is not performed, process200 begins with edge deleting a first width about a portion of theperimeter of the substrate, see 205. The edge deletion may remove onlythe first conductive layer or may also remove a diffusion barrier, ifpresent. In one embodiment, the substrate is glass and includes a sodiumdiffusion barrier and a transparent conducting layer thereon, e.g. atin-oxide based transparent metal oxide conducting layer. The dottedarea in FIG. 2B denotes the first conductive layer. Thus, after edgedeletion according to process 205, a width A is removed from three sidesof the perimeter of substrate 230. This width is typically, but notnecessarily, a uniform width. A second width, B, is described below.Where width A and/or width B are not uniform, then their relativemagnitudes with respect to each other are in terms of their averagewidth.

As a result of the removal of the first width A at 205, there is a newlyexposed edge of the lower conductive layer. In certain embodiments, atleast a portion of this edge of the first conductive layer may beoptionally tapered, see 207 and 209. The underlying diffusion barrierlayer may also be tapered. Tapering the edge of one or more devicelayers, prior to fabricating subsequent layers thereon, has unexpectedadvantages in device structure and performance The edge tapering processis described in more detail in U.S. Pat. No. 9,454,053, which is hereinincorporated by reference in its entirety. Although edge tapering isshown at both 207 and 209 in FIG. 2A, if performed, edge tapering wouldtypically be performed once (e.g., at 207 or 209).

In certain embodiments, the lower conductive layer is optionallypolished before or after edge tapering, see 208.

After removal of the first width A, and optional polishing and/oroptional edge tapering as described above, the EC device is depositedover the surface of substrate 230, see 210. This EC stack deposition isfurther described in relation to FIG. 2D. This deposition includes oneor more material layers of the optical device and the second conductinglayer, e.g. a transparent conducting layer such as indium tin oxide(ITO). The depicted coverage is the entire substrate, but there could besome masking due to a carrier that must hold the glass in place. In oneembodiment, the entire area of the remaining portion of the firstconductive layer is covered including overlapping the first conductorabout the first width A previously removed. This allows for overlappingregions in the final device architecture.

In particular embodiments, electromagnetic radiation is used to performedge deletion and provide a peripheral region of the substrate, e.g., toremove transparent conductive layer or more layers (up to and includingthe top conductive layer and any vapor barrier applied thereto),depending upon the process step. In one embodiment, the edge deletion isperformed at least to remove material including the transparentconductive layer on the substrate, and optionally also removing adiffusion barrier if present. In certain embodiments, edge deletion isused to remove a surface portion of the substrate, e.g., float glass,and may go to a depth not to exceed the thickness of the compressionzone. Edge deletion is performed, e.g., to create a good surface forsealing by at least a portion of the primary seal and the secondary sealof the IGU. For example, a transparent conductive layer can sometimeslose adhesion when the conductive layer spans the entire area of thesubstrate and thus has an exposed edge, despite the presence of asecondary seal. Also, it is believed that when metal oxide and otherfunctional layers have such exposed edges, they can serve as a pathwayfor moisture to enter the bulk device and thus compromise the primaryand secondary seals.

Edge deletion is described herein as being performed on a substrate thatis already cut to size. However, edge deletion can be done before asubstrate is cut from a bulk glass sheet in other disclosed embodiments.For example, non-tempered float glass may be cut into individual litesafter an EC device is patterned thereon. Methods described herein can beperformed on a bulk sheet and then the sheet cut into individual EClites. In certain embodiments, edge deletion may be carried out in someedge areas prior to cutting the EC lites, and again after they are cutfrom the bulk sheet. In certain embodiments, all edge deletion isperformed prior to excising the lites from the bulk sheet. Inembodiments employing “edge deletion” prior to cutting the panes,portions of the coating on the glass sheet can be removed inanticipation of where the cuts (and thus edges) of the newly formed EClites will be. In other words, there is no actual substrate edge yet,only a defined area where a cut will be made to produce an edge. Thus“edge deletion” is meant to include removing one or more material layersin areas where a substrate edge is anticipated to exist. Methods offabricating EC lites by cutting from a bulk sheet after fabrication ofthe EC device thereon are described in U.S. patent application, Ser. No.12/941,882 (now U.S. Pat. No. 8,164,818), filed Nov. 8, 2010, and U.S.patent application, Ser. No. 13/456,056, filed Apr. 25, 2012, eachtitled “Electrochromic Window Fabrication Methods” each of which ishereby incorporated by reference in its entirety. One of ordinary skillin the art would appreciate that if one were to carry out methodsdescribed herein on a bulk glass sheet and then cut individual litestherefrom, in certain embodiments masks may have to be used, whereaswhen performed on a lite of desired end size, masks are optional.

Exemplary electromagnetic radiation includes UV, lasers, and the like.For example, material may be removed with directed and focused energy atone or more of the wavelengths 248 nm, 355 nm (UV), 1030 nm (IR, e.g.disk laser), 1064 nm (e.g. Nd:YAG laser), and 532 nm (e.g. green laser).Laser irradiation is delivered to the substrate using, e.g. opticalfiber or open beam path. The ablation can be performed from either thesubstrate side or the EC film side depending on the choice of thesubstrate handling equipment and configuration parameters. The energydensity required to ablate the film thickness is achieved by passing thelaser beam through an optical lens. The lens focuses the laser beam tothe desired shape and size. In one embodiment, a “top hat” beamconfiguration is used, e.g., having a focus area of between about 0.005mm² to about 2 mm². In one embodiment, the focusing level of the beam isused to achieve the required energy density to ablate the EC film stack.In one embodiment, the energy density used in the ablation is betweenabout 2 J/cm² and about 6 J/cm².

During a laser edge delete process, a laser spot is scanned over thesurface of the EC device, along the periphery. In one embodiment, thelaser spot is scanned using a scanning F theta lens. Homogeneous removalof the EC film is achieved, e.g., by overlapping the spots' area duringscanning In one embodiment, the overlap is between about 5% and about100%, in another embodiment between about 10% and about 90%, in yetanother embodiment between about 10% and about 80%. Various scanningpatterns may be used, e.g., scanning in straight lines, curved lines,and various patterns may be scanned, e.g., rectangular or other shapedsections are scanned which, collectively, create the peripheral edgedeletion area. In one embodiment the scanning lines (or “pens,” i.e.lines created by adjacent or overlapping laser spots, e.g. square,round, etc.) are overlapped at the levels described above for spotoverlap. That is, the area of the ablated material defined by the pathof the line previously scanned is overlapped with later scan lines sothat there is overlap. That is, a pattern area ablated by overlapping oradjacent laser spots is overlapped with the area of a subsequentablation pattern. For embodiments where overlapping is used, spots,lines or patterns, a higher frequency laser, e.g. in the range ofbetween about 11 KHz and about 500 KHz, may be used. In order tominimize heat related damage to the EC device at the exposed edge (aheat affected zone or “HAZ”), shorter pulse duration lasers are used. Inone example, the pulse duration is between about 100 fs (femtosecond)and about 100 ns (nanosecond), in another embodiment the pulse durationis between about 1 ps (picosecond) and about 50 ns, in yet anotherembodiment the pulse duration is between about 20 ps and about 30 ns.Pulse duration of other ranges can be used in other embodiments.

Referring again to FIGS. 2A and 2B, process flow 200 continues withremoving a second width, B, narrower than the first width A, aboutsubstantially the entire perimeter of the substrate, see 215. This mayinclude removing material down to the glass or to a diffusion barrier,if present. After process flow 200 is complete up to 215, e.g. on arectangular substrate as depicted in FIG. 2B, there is a perimeter area,with width B, where there is none of the first transparent conductor,the one or more material layers of the device, or the second conductinglayer —removing width B has exposed diffusion barrier or substrate.Within this perimeter area is the device stack, including the firsttransparent conductor surrounded on three sides by overlapping one ormore material layers and the second conductive layer. On the remainingside (e.g., the bottom side in FIG. 2B) there is no overlapping portionof the one or more material layers and the second conductive layer. Itis proximate this remaining side (e.g., bottom side in FIG. 2B) that theone or more material layers and the second conductive layer are removedin order to expose a portion (bus bar pad expose, or “BPE”), 235, of thefirst conductive layer, see 220. The BPE 235 need not run the entirelength of that side, it need only be long enough to accommodate the busbar and leave some space between the bus bar and the second conductivelayer so as not to short on the second conductive layer. In oneembodiment, the BPE 235 spans the length of the first conductive layeron that side.

In various embodiments, a BPE is where a portion of the material layersare removed down to the lower electrode or other conductive layer (e.g.a transparent conducting oxide layer), in order to create a surface fora bus bar to be applied and thus make electrical contact with theelectrode. The bus bar applied can be a soldered bus bar, and ink busbar and the like. A BPE typically has a rectangular area, but this isnot necessary; the BPE may be any geometrical shape or an irregularshape. For example, depending upon the need, a BPE may be circular,triangular, oval, trapezoidal, and other polygonal shapes. The shape maybe dependent on the configuration of the EC device, the substratebearing the EC device (e.g. an irregular shaped window), or even, e.g.,a more efficient (e.g. in material removal, time, etc.) laser ablationpattern used to create it. In one embodiment, the BPE spans at leastabout 50% of the length of one side of an EC device. In one embodiment,the BPE spans at least about 80% of the length of one side of an ECdevice. Typically, but not necessarily, the BPE is wide enough toaccommodate the bus bar, but should allow for some space at leastbetween the active EC device stack and the bus bar. In one embodiment,the BPE is substantially rectangular, the length approximating one sideof the EC device and the width is between about 5 mm and about 15 mm, inanother embodiment between about 5 mm and about 10 mm, and in yetanother embodiment between about 7 mm and about 9 mm As mentioned, a busbar may be between about 1 mm and about 5 mm wide, typically about 3 mmwide.

As mentioned, the BPE is fabricated wide enough to accommodate the busbar's width and also leave space between the bus bar and the EC device(as the bus bar is only supposed to touch the lower conductive layer).The bus bar width may exceed that of the BPE (and thus there is bus barmaterial touching both the lower conductor and glass (and/or diffusionbarrier) on area 241), as long as there is space between the bus bar andthe EC device (in embodiments where there is an L3 isolation scribe, thebus bar may contact the deactivated portion). In embodiments where thebus bar width is fully accommodated by the BPE, that is, the bus bar isentirely atop the lower conductor, the outer edge, along the length, ofthe bus bar may be aligned with the outer edge of the BPE, or inset byabout 1 mm to about 3 mm Likewise, the space between the bus bar and theEC device is between about 1 mm and about 3 mm, in another embodimentbetween about 1 mm and 2 mm, and in another embodiment about 1.5 mmFormation of BPEs is described in more detail below, with respect to anEC device having a lower electrode that is a TCO. This is forconvenience only, the electrode could be any suitable electrode for anoptical device, transparent or not.

To make a BPE, an area of the bottom TCO (e.g. first TCO) is cleared ofdeposited material so that a bus bar can be fabricated on the TCO. Inone embodiment, this is achieved by laser processing which selectivelyremoves the deposited film layers while leaving the bottom TCO exposedin a defined area at a defined location. In one embodiment, theabsorption characteristics of the bottom electrode and the depositedlayers are exploited in order to achieve selectivity during laserablation, that is, so that the EC materials on the TCO are selectivelyremoved while leaving the TCO material intact. In certain embodiments,an upper portion (depth) of the TCO layer is also removed in order toensure good electrical contact of the bus bar, e.g., by removing anymixture of TCO and EC materials that might have occurred duringdeposition. In certain embodiments, when the BPE edges are lasermachined so as to minimize damage at these edges, the need for an L3isolation scribe line to limit leakage currents can be avoided—thiseliminates a process step, while achieving the desired deviceperformance results.

In certain embodiments, the electromagnetic radiation used to fabricatea BPE is the same as described above for performing edge deletion. The(laser) radiation is delivered to the substrate using either opticalfiber or the open beam path. The ablation can be performed from eitherglass side or the film side depending on the choice of theelectromagnetic radiation wavelength. The energy density required toablate the film thickness is achieved by passing the laser beam throughan optical lens. The lens focuses the laser beam to the desired shapeand size, e.g. a “top hat” having the dimensions described above, in oneembodiment, having an energy density of between about 0.5 J/cm² andabout 4 J/cm². In one embodiment, laser scan overlapping for BPE is doneas described above for laser edge deletion. In certain embodiments,variable depth ablation is used for BPE fabrication.

In certain embodiments, e.g. due to the selective nature of theabsorption in an EC film, the laser processing at the focal planeresults in some amount (between about 10 nm and about 100 nm) ofresidue, e.g. tungsten oxide, remaining on the exposed area of the lowerconductor. Since many EC materials are not as conductive as theunderlying conductive layer, the bus bar fabricated on this residue doesnot make full contact with the underlying conductor, resulting involtage drop across the bus bar to lower conductor interface. Thevoltage drop impacts coloration of the device as well as impacts theadhesion of the bus bar to the lower conductor. One way to overcome thisproblem is to increase the amount of energy used for film removal,however, this approach results in forming a trench at the spot overlap,unacceptably depleting the lower conductor. To overcome this problem thelaser ablation above the focal plane is performed, i.e. the laser beamis defocused. In one embodiment, the defocusing profile of the laserbeam is a modified top hat, or “quasi top hat.” By using a defocusedlaser profile, the fluence delivered to the surface can be increasedwithout damaging the underlying TCO at spot overlap region. This methodminimizes the amount of residue left in on the exposed lower conductivelayer and thus allows for better contact of the bus bar to the lowerconductive layer.

Referring again to FIGS. 2A and 2B, after forming the BPE, bus bars areapplied to the device, one on exposed area 235 of the first conductivelayer (e.g., first TCO) and one on the opposite side of the device, onthe second conductive layer (e.g., second TCO), on a portion of thesecond conductive layer that is not above the first conductive layer,see 225. This placement of the bus bar 1 on the second conductive layeravoids coloration under the bus bar and the other associated issues withhaving a functional device under this bus bar. In this example, thereare no laser isolation scribes necessary in fabrication of thedevice—this is a radical departure from conventional fabricationmethods, where one or more isolation scribes leave non-functional deviceportions remaining in the final construct.

FIG. 2B indicates cross-section cuts Z-Z′ and W-W′ of device 240. Thecross-sectional views of device 240 at Z-Z′ and W-W′ are shown in FIG.2C. The depicted layers and dimensions are not to scale, but are meantto represent functionally the configuration. In this example, thediffusion barrier was removed when width A and width B were fabricated.Specifically, perimeter area 241 is free of first conductive layer anddiffusion barrier; although in one embodiment the diffusion barrier isleft intact to the edge of the substrate about the perimeter on one ormore sides. In another embodiment, the diffusion barrier is co-extensivewith the one or more material layers and the second conductive layer(thus width A is fabricated at a depth to the diffusion barrier, andwidth B is fabricated to a depth sufficient to remove the diffusionbarrier). In this example, there is an overlapping portion, 245, of theone or more material layers about three sides of the functional device.On one of these overlapping portions, on the second TCO, bus bar 1 isfabricated. In one embodiment, a vapor barrier layer is fabricatedco-extensive with the second conductive layer. A vapor barrier istypically highly transparent, e.g. aluminum zinc oxide, a tin oxide,silicon dioxide and mixtures thereof, amorphous, crystalline or mixedamorphous-crystalline. In this embodiment, a portion of the vaporbarrier is removed in order to expose the second conductive layer forbus bar 1. This exposed portion is analogous to area 235, the BPE forbus bar 2. In certain embodiments, the vapor barrier layer is alsoelectrically conductive, and exposure of the second conductive layerneed not be performed, i.e. the bus bar may be fabricated on the vaporbarrier layer. For example, the vapor barrier layer may be ITO, e.g.amorphous ITO, and thus be sufficiently electrically conductive for thispurpose. The amorphous morphology of the vapor barrier may providegreater hermeticity than a crystalline morphology. In certain instances,the vapor barrier may be deposited using chemical vapor deposition (CVD)or atomic layer deposition (ALD), and may include a metal nitride thatis electrically conductive, a silicon nitride, a silicon oxide ormixtures thereof.

FIG. 2D provides another flowchart describing a method of fabricating anelectrochromic device or precursor according to certain embodiments. Themethod described in FIG. 2D focuses on the deposition steps. The method260 begins by either (a) receiving a substrate having a first conductivelayer thereon, or (b) depositing the first conductive layer on thesubstrate, see 261. As mentioned above, in various embodiments thesubstrate includes the first conductive layer thereon, and there is noneed to separately deposit the first conductive layer. In otherembodiments, the conductive layer may be deposited prior to depositionof the remaining layers. Deposition of the second conductive layer isdiscussed further below. In certain embodiments, these details may alsoapply to the deposition of the first conductive layer.

The method continues with deposition of the electrochromic layer, see263. In many cases, the electrochromic layer is formed throughsputtering. In certain embodiments where the electrochromic layer ishomogeneous, the following conditions may be used to deposit theelectrochromic layer. The electrochromic layer may be formed bysputtering using one or more metal-containing targets and a sputter gasincluding between about 40% and about 80% O₂ and between about 20% andabout 60% Ar. Each target may include one or more metals such astungsten and molybdenum. The substrate upon which the electrochromiclayer is deposited may be heated, at least intermittently, to betweenabout 150° C. and about 450° C. (in some cases between about 250° C. and350° C.) during formation of the electrochromic layer. Theelectrochromic layer may be deposited to a thickness between about 500and 600 nm.

In some embodiments where the ion conductor layer is omitted, theelectrochromic layer may be deposited as two or more layers or a gradedlayer. One of the layers or a portion of the graded layer may beoxygen-rich in comparison to the other layer or the remainder of thegraded layer. The oxygen-rich portion may be superstoichiometric withrespect to oxygen. Typically, the oxygen-rich layer or portion is incontact with the counter electrode layer. In other embodiments, theoxygen rich material at the interface may be supplied in the form of thecounter electrode material instead of or in addition to theelectrochromic material.

In cases where the electrochromic layer is deposited as two or morelayers (one of which is oxygen-rich), the following conditions may beused. In some such cases, the first layer of the electrochromic layermay be between about 350 nm and about 450 nm thick. The first layer maybe formed through sputtering using one or more targets and a firstsputter gas including between about 40% and about 80% O₂ and betweenabout 20% Ar and about 60% Ar. The targets may include one or more metalsuch as tungsten and molybdenum. The second layer may be between about100 nm and about 200 nm thick. The second layer may be formed throughsputtering using one or more targets and a second sputter gas includingbetween about 70% and 100% O₂ and between 0% Ar and about 30% Ar. Inthis embodiment, heat may be applied, for example by heating substrate,at least intermittently, to between about 150° C. and about 450° C.during deposition of the first electrochromic layer, but not (orsubstantially not) heating during deposition of the secondelectrochromic layer. In a more specific embodiment, the firstelectrochromic layer is about 400 nm thick; the first sputter gasincludes between about 50% and about 60% O₂ and between about 40% andabout 50% Ar; the second electrochromic layer is about 150 nm thick; andthe second sputter gas is substantially pure O₂. In this embodiment,heat is applied, at least intermittently, to between about 200° C. andabout 350° C. during formation of the first electrochromic layer but not(or substantially not) during formation of the second electrochromiclayer.

In cases where the electrochromic layer is deposited as a graded layerwith a graded oxygen composition, the following conditions may be usedto deposit the electrochromic layer. The electrochromic layer may beformed through sputtering using one or more metal-containing targets anda sputter gas, where the sputter gas includes between about 40% andabout 80% O₂ and between about 20% and about 60% Ar at the start ofsputtering the electrochromic layer, and the sputter gas includesbetween about 70% and 100% O₂ and between 0% and about 30% Ar at the endof sputtering the electrochromic layer. The substrate may be heated, atleast intermittently, to between about 200° C. and about 350° C. at thebeginning of formation of the electrochromic layer, but not heatedduring deposition of at least a final portion of the electrochromiclayer. This description assumes that the electrochromic layer isdeposited before the counter electrode layer, as shown in FIG. 2D. Incases where the electrochromic layer is deposited as a graded layerafter formation of the counter electrode layer, the details regardingthe “initial”/“start” and “final”/“end” portions of the sputtering maybe reversed. In either case, the electrochromic material with the higheroxygen concentration may be in contact with the counter electrode layer.

Regardless of the structure of the electrochromic layer, the pressure inthe deposition station or chamber during formation of the electrochromiclayer may be between about 1 and about 75 mTorr, or between about 5 andabout 50 mTorr, or between about 10 and about 20 mTorr. In oneembodiment, the power density used to sputter the one or more targetsmay be between about 2 Watts/cm² and about 50 Watts/cm² (determinedbased on the power applied divided by the surface area of the target);in another embodiment between about 10 Watts/cm² and about 20 Watts/cm²;and in yet another embodiment between about 15 Watts/cm² and about 20Watts/cm². In some embodiments, the power delivered to effect sputteringis provided via direct current (DC). In other embodiments, pulsed DC/ACreactive sputtering is used. In one embodiment, where pulsed DC/ACreactive sputtering is used, the frequency is between about 20 kHz andabout 400 kHz, in another embodiment between about 20 kHz and about 50kHz, in yet another embodiment between about 40 kHz and about 50 kHz, inanother embodiment about 40 kHz. The above conditions may be used in anycombination with one another to effect deposition of a high qualityelectrochromic layer. In one embodiment, the distance between the target(cathode or source) to the substrate surface is between about 35 mm andabout 150 mm; in another embodiment between about 45 mm and about 130mm; and in another embodiment between about 70 mm and about 100 mm Thesesame distances may apply to other targets used to deposit other layersof the device.

Next, the method continues with the optional deposition of the ionconducting layer, see 263. When present, the ion conducting layer may beprovided in a number of different ways. For instance, the ion conductorlayer may be formed through sputtering, vapor-based techniques, sol-geltechniques, etc. In many cases, the ion conducting layer is omitted.

Then, the method continues with deposition of the counter electrodelayer, see 267. Much like the electrochromic layer, the counterelectrode layer may be deposited as a homogenous layer, two or morelayers, or a graded layer. In cases where the counter electrode isdeposited as two or more layers or a graded layer, one of the layers ora portion of the graded layer may be oxygen-rich in comparison to theother layer or the remaining portion of the graded layer. Theoxygen-rich layer or portion may be positioned in direct physicalcontact with the electrochromic material in the electrochromic layer. Insuch cases, the deposition conditions may change between depositing thefirst layer and the second layer, or between depositing the initialportion of the graded layer and the final portion of the graded layer.The oxygen concentrations and substrate temperatures recited above withrespect to deposition of an electrochromic layer may also apply todeposition of a counter electrode layer in various embodiments.Generally, the layer or the portion of the graded layer that isoxygen-rich may be formed using a sputter gas having a higherconcentration of oxygen and a lower concentration of inert gas comparedto the sputter gas used to deposit the other layer or the remainingportion of the graded layer.

In certain implementations, a sputter gas used to form the counterelectrode may include between about 30% and about 100% oxygen, inanother embodiment between about 80% and about 100% oxygen, in yetanother embodiment between about 95% and about 100% oxygen, in anotherembodiment about 100% oxygen. In one embodiment, the power density usedto sputter the CE target is between about 2 Watts/cm² and about 50Watts/cm² (determined based on the power applied divided by the surfacearea of the target); in another embodiment between about 5 Watts/cm² andabout 20 Watts/cm²; and in yet another embodiment between about 8Watts/cm² and about 10 Watts/cm², in another embodiment about 8Watts/cm². In some embodiments, the power delivered to effect sputteringis provided via direct current (DC). In other embodiments, pulsed DC/ACreactive sputtering is used. In one embodiment, where pulsed DC/ACreactive sputtering is used, the frequency is between about 20 kHz andabout 400 kHz, in another embodiment between about 20 kHz and about 50kHz, in yet another embodiment between about 40 kHz and about 50 kHz, inanother embodiment about 40 kHz. The pressure in the deposition stationor chamber, in one embodiment, is between about 1 and about 50 mTorr, inanother embodiment between about 20 and about 40 mTorr, in anotherembodiment between about 25 and about 35 mTorr, in another embodimentabout 30 mTorr. In certain embodiments, the counter electrode layer isdeposited to a thickness of between about 150 and 350 nm; in yet anotherembodiment between about 200 and about 250 nm thick.

Next, the method continues with deposition of the second conductivelayer, see 269. The recited conditions may be employed to form a thin,low-defect layer of indium tin oxide by sputtering a target containingindium oxide in tin oxide, e.g. with an argon sputter gas with orwithout oxygen. This is merely one example, and other materials andconditions may be used in other cases. In one embodiment, the thicknessof the TCO layer is between about 5 nm and about 10,000 nm, in anotherembodiment between about 10 nm and about 1,000 nm; in yet anotherembodiment between about 10 nm and about 500 nm. In one embodiment, thesubstrate temperature during deposition of the second conducting layeris between about 20° C. and about 300° C., in another embodiment betweenabout 20° C. and about 250° C., and in another embodiment between about80° C. and about 225° C. In one embodiment, depositing the TCO layerincludes sputtering a target including between about 80% (by weight) toabout 99% of In₂O₃ and between about 1% and about 20% SnO₂ using aninert gas, optionally with oxygen. In a more specific embodiment, thetarget is between about 85% (by weight) to about 97% of In₂O₃ andbetween about 3% and about 15% SnO₂. In another embodiment, the targetis about 90% of In₂O₃ and about 10% SnO₂. In one embodiment, the gascomposition contains between about 0.1% and about 3% oxygen, in anotherembodiment between about 0.5% and about 2% oxygen, in yet anotherembodiment between about 1% and about 1.5% oxygen, in another embodimentabout 1.2% oxygen. In one embodiment, the power density used to sputterthe TCO target is between about 0.5 Watts/cm² and about 10 Watts/cm²(determined based on the power applied divided by the surface area ofthe target); in another embodiment between about 0.5 Watts/cm² and about2 Watts/cm²; and in yet another embodiment between about 0.5 Watts/cm²and about 1 Watts/cm², in another embodiment about 0.7 Watts/cm². Insome embodiments, the power delivered to effect sputtering is providedvia direct current (DC). In other embodiments, pulsed DC/AC reactivesputtering is used. In one embodiment, where pulsed DC/AC reactivesputtering is used, the frequency is between about 20 kHz and about 400kHz, in another embodiment between about 50 kHz and about 100 kHz, inyet another embodiment between about 60 kHz and about 90 kHz, in anotherembodiment about 80 kHz. The pressure in the deposition station orchamber, in one embodiment, is between about 1 and about 10 mTorr, inanother embodiment between about 2 and about 5 mTorr, in anotherembodiment between about 3 and about 4 mTorr, in another embodimentabout 3.5 mTorr. In one embodiment, the indium tin oxide layer isbetween about 20% (atomic) In and about 40% In; between about 2.5% Snand about 12.5% Sn; and between about 50% 0 and about 70% O; in anotherembodiment, between about 25% In and about 35% In; between about 5.5% Snand about 8.5% Sn; and between about 55% O and about 65% O; and inanother embodiment, about 30% In, about 8% Sn; and about 62% O. Theabove conditions may be used in any combination with one another toeffect deposition of a high quality indium tin oxide layer.

When practicing the method of FIG. 2D, one or more of the depositedlayers may be lithiated prior to deposition of the next layer. Forinstance, one or more of the electrochromic layer, the optional ionconducting layer, and the counter electrode layer may be lithiated. Inone example, the electrochromic layer is lithiated. In another example,the counter electrode layer is lithiated. In another example, the ionconductor layer is lithiated. In another example, both theelectrochromic layer and the counter electrode layer are lithiated. Inanother example, the electrochromic layer, counter electrode layer, andion conducting layer are all lithiated. In another example, theelectrochromic layer and the ion conductor layer are lithiated. Inanother example, the counter electrode layer and the ion conducing layerare lithiated. Further, any of these layers may be lithiated duringdeposition of that layer. In some cases, one portion of a layer may bedeposited, then lithiated, and then the remaining portion of that layermay be deposited. In one example, a first portion of the electrochromiclayer is deposited, then lithiated, and then a second portion of theelectrochromic layer is deposited. In another example, a first portionof the counter electrode layer is deposited, then lithiated, and then asecond portion of the counter electrode layer is deposited. These firstand second portions of the relevant layer may be deposited according tothe same conditions, or different conditions. In some cases, the firstand second portions of the relevant layer may have differentcompositions.

In cases where the ion conducting layer is omitted, lithiation of theelectrochromic and/or counter electrode layers may promote formation ofan interfacial region between the electrochromic layer and the counterelectrode layer, where the interfacial region includes material that isionically conductive and substantially electronically insulating. Forexample, in some such embodiments, when the electrochromic and counterelectrode materials are abutted and one or both of the materials containan excess of oxygen (e.g., above stoichiometric levels), the lithiumintercalation and subsequent heating allows a chemical change at theinterface between the two electrode materials (e.g., between theelectrochromic material and the counter electrode material), forming anionically conductive and electrically insulating material in aninterfacial region between the electrochromic layer and the counterelectrode layer. For example, the multi-step thermal conditioning asdescribed herein may promote formation of the ionically conductive andelectrically insulating material.

The operations shown in FIG. 2D may be used to form an electrochromicdevice precursor in various embodiments. In order to form anelectrochromic device from the electrochromic device precursor, one ormore steps may be taken as described above. As mentioned, one techniquethat may be used to form an electrochromic device from an electrochromicdevice precursor is multi-step thermal conditioning. The conditioningmay involve a series of heating operations including heating thesubstrate under an inert atmosphere, heating the substrate under oxygenatmosphere, and heating the substrate in air.

In one embodiment, stacks formed as described in FIG. 2D are heated(either before or after depositing the second conductive layer at 269)at between about 150° C. and about 450° C., for between about 10 minutesand about 30 minutes under Ar, and then for between about 1 minute andabout 15 minutes under O₂. After this processing, the stack is processedfurther by heating the stack in air at between about 250° C. and about350° C., for between about 20 minutes and about 40 minutes. In aparticular example the stack is processed by heating the stack at about250° C. for about 15 minutes under inert atmosphere, followed by 5minutes under O₂ atmosphere, then heating the stack in air at about 300°C. for about 30 minutes. Flowing a current between the electrochromiclayer and the counter electrode layer as part of an initial activationcycle of the electrochromic device can also be performed.

While FIG. 2D assumes that the electrochromic layer is deposited priorto the counter electrode layer, this is not always the case. In certainimplementations, operations 263 and 267 may be reversed such that thecounter electrode layer is deposited prior to the electrochromic layer.

III. Apparatus for Fabricating Electrochromic Devices and Precursors

An integrated deposition system may be employed to fabricateelectrochromic devices on, for example, architectural glass or othersubstrates. The electrochromic devices may be used to make insulatedglass units (IGUs) which in turn may be used to make electrochromicwindows. The term “integrated deposition system” means an apparatus forfabricating electrochromic devices on optically transparent andtranslucent substrates. The apparatus has multiple stations, eachdevoted to a particular unit operation such as depositing a particularcomponent (or portion of a component) of an electrochromic device, aswell as cleaning, etching, and temperature control of such device orportion thereof. The multiple stations are fully integrated such that asubstrate on which an electrochromic device is being fabricated can passfrom one station to the next without being exposed to an externalenvironment. Integrated deposition systems operate with a controlledambient environment inside the system where the process stations arelocated. A fully integrated system allows for better control ofinterfacial quality between the layers deposited. Interfacial qualityrefers to, among other factors, the quality of the adhesion betweenlayers and the lack of contaminants in the interfacial region. The term“controlled ambient environment” means a sealed environment separatefrom an external environment such as an open atmospheric environment ora clean room. In a controlled ambient environment at least one ofpressure and gas composition is controlled independently of theconditions in the external environment. Generally, though notnecessarily, a controlled ambient environment has a pressure belowatmospheric pressure; e.g., at least a partial vacuum. The conditions ina controlled ambient environment may remain constant during a processingoperation or may vary over time. For example, a layer of anelectrochromic device may be deposited under vacuum in a controlledambient environment and at the conclusion of the deposition operation,the environment may be backfilled with purge or reagent gas and thepressure increased to, e.g., atmospheric pressure for processing atanother station, and then a vacuum reestablished for the next operationand so forth.

In one embodiment, the system includes a plurality of depositionstations aligned in series and interconnected and operable to pass asubstrate from one station to the next without exposing the substrate toan external environment. The plurality of deposition stations comprise(i) a first deposition station containing one or more targets fordepositing a cathodically coloring electrochromic layer; (ii) a secondoptional deposition station containing one or more targets fordepositing an ion conducting layer; and (iii) a third deposition stationcontaining one or more targets for depositing a counter electrode layer.The second deposition station may be omitted in certain cases. Forinstance, the apparatus may not include any target for depositing aseparate ion conductor layer. The system also includes a controllercontaining program instructions for passing the substrate through theplurality of stations in a manner that sequentially deposits on thesubstrate (i) an electrochromic layer, (ii) an (optional) ion conductinglayer, and (iii) a counter electrode layer to form a stack. In caseswhere the electrochromic layer or counter electrode layer includes twoor more layers, the layers may be formed in different stations or in thesame station, depending on the desired composition of each layer, amongother factors. In one example, a first station may be used to depositthe electrochromic layer, a second station may be used to deposit afirst layer of the counter electrode layer, and a third station may beused to deposit a second layer of the counter electrode layer.

In one embodiment, the plurality of deposition stations are operable topass a substrate from one station to the next without breaking vacuum.In another embodiment, the plurality of deposition stations areconfigured to deposit the electrochromic layer, the optional ionconducting layer, and the counter electrode layer on an architecturalglass substrate. In another embodiment, the integrated deposition systemincludes a substrate holder and transport mechanism operable to hold thearchitectural glass substrate in a vertical orientation while in theplurality of deposition stations. In yet another embodiment, theintegrated deposition system includes one or more load locks for passingthe substrate between an external environment and the integrateddeposition system. In another embodiment, the plurality of depositionstations include at least two stations for depositing a layer selectedfrom the group consisting of the electrochromic layer, the ionconducting layer, and the counter electrode layer.

In some embodiments, the integrated deposition system includes one ormore lithium deposition stations, each including a lithium containingtarget. In one embodiment, the integrated deposition system contains twoor more lithium deposition stations. In one embodiment, the integrateddeposition system has one or more isolation valves for isolatingindividual process stations from each other during operation. In oneembodiment, the one or more lithium deposition stations have isolationvalves. In this document, the term “isolation valves” means devices toisolate depositions or other processes being carried out one stationfrom processes at other stations in the integrated deposition system. Inone example, isolation valves are physical (solid) isolation valveswithin the integrated deposition system that engage while the lithium isdeposited. Actual physical solid valves may engage to totally orpartially isolate (or shield) the lithium deposition from otherprocesses or stations in the integrated deposition system. In anotherembodiment, the isolation valves may be gas knifes or shields, e.g., apartial pressure of argon or other inert gas is passed over areasbetween the lithium deposition station and other stations to block ionflow to the other stations. In another example, isolation valves may bean evacuated regions between the lithium deposition station and otherprocess stations, so that lithium ions or ions from other stationsentering the evacuated region are removed to, e.g., a waste streamrather than contaminating adjoining processes. This is achieved, e.g.,via a flow dynamic in the controlled ambient environment viadifferential pressures in a lithiation station of the integrateddeposition system such that the lithium deposition is sufficientlyisolated from other processes in the integrated deposition system.Again, isolation valves are not limited to lithium deposition stations.

In some embodiments, the integrated deposition system includes one ormore stations for depositing a conductive layer (e.g., a transparentconductive oxide layer, sometimes referred to as TCO). In cases whereboth the first and second conductive layers are deposited on thesubstrate, two stations may be provided, each dedicated to depositingone of the conductive layers. In other embodiments, a single station maybe used to deposit both conductive layers. In cases where only a singleconductive layer is deposited, only a single conductive layer depositionstation is needed. For instance, in many cases the substrate is receivedwith the first conductive layer provided thereon, and only the secondconductive layer is deposited during fabrication of the electrochromicdevice.

FIG. 3A depicts in schematic fashion an integrated deposition system 300in accordance with certain embodiments. In this example, system 300includes an entry load lock, 302, for introducing the substrate to thesystem, and an exit load lock, 304, for removal of the substrate fromthe system. The load locks allow substrates to be introduced and removedfrom the system without disturbing the controlled ambient environment ofthe system. Integrated deposition system 300 has a module, 306, with aplurality of deposition stations; an EC layer deposition station, an IClayer deposition station and a CE layer deposition station. In thebroadest sense, integrated deposition systems need not have load locks,e.g., module 306 could alone serve as the integrated deposition system.For example, the substrate may be loaded into module 306, the controlledambient environment established and then the substrate processed throughvarious stations within the system. Individual stations within anintegrated deposition systems can contain heaters, coolers, varioussputter targets and means to move them, RF and/or DC power sources andpower delivery mechanisms, etching tools e.g. plasma etch, gas sources,vacuum sources, glow discharge sources, process parameter monitors andsensors, robotics, power supplies, and the like.

FIG. 3B depicts a segment (or simplified version) of integrateddeposition system 300 in a perspective view and with more detailincluding a cutaway view of the interior. In this example, system 300 ismodular, where entry load lock 302 and exit load lock 304 are connectedto deposition module 306. There is an entry port, 310, for loading, forexample, architectural glass substrate 325 (load lock 304 has acorresponding exit port). Substrate 325 is supported by a pallet, 320,which travels along a track, 315. In this example, pallet 320 issupported by track 315 via hanging but pallet 320 could also besupported atop a track located near the bottom of apparatus 300 or atrack, e.g. mid-way between top and bottom of apparatus 300. Pallet 320can translate (as indicated by the double headed arrow) forward and/orbackward through system 300. For example during lithium deposition, thesubstrate may be moved forward and backward in front of a lithiumtarget, 330, making multiple passes in order to achieve a desiredlithiation. Pallet 320 and substrate 325 are in a substantially verticalorientation. A substantially vertical orientation is not limiting, butit may help to prevent defects because particulate matter that may begenerated, e.g., from agglomeration of atoms from sputtering, will tendto succumb to gravity and therefore not deposit on substrate 325. Also,because architectural glass substrates tend to be large, a verticalorientation of the substrate as it traverses the stations of theintegrated deposition system enables coating of thinner glass substratessince there are less concerns over sag that occurs with thicker hotglass.

Target 330, in this case a cylindrical target, is oriented substantiallyparallel to and in front of the substrate surface where deposition is totake place (for convenience, other sputter means are not depicted here).Substrate 325 can translate past target 330 during deposition and/ortarget 330 can move in front of substrate 325. The movement path oftarget 330 is not limited to translation along the path of substrate325. Target 330 may rotate along an axis through its length, translatealong the path of the substrate (forward and/or backward), translatealong a path perpendicular to the path of the substrate, move in acircular path in a plane parallel to substrate 325, etc. Target 330 neednot be cylindrical, it can be planar or any shape necessary fordeposition of the desired layer with the desired properties. Also, theremay be more than one target in each deposition station and/or targetsmay move from station to station depending on the desired process.

Integrated deposition system 300 also has various vacuum pumps, gasinlets, pressure sensors and the like that establish and maintain acontrolled ambient environment within the system. These components arenot shown, but rather would be appreciated by one of ordinary skill inthe art. System 300 is controlled, e.g., via a computer system or othercontroller, represented in FIG. 3B by an LCD and keyboard, 335. One ofordinary skill in the art would appreciate that embodiments herein mayemploy various processes involving data stored in or transferred throughone or more computer systems. Embodiments also relate to the apparatus,such computers and microcontrollers, for performing these operations.These apparatus and processes may be employed to deposit electrochromicmaterials of methods herein and apparatus designed to implement them.The control apparatus may be specially constructed for the requiredpurposes, or it may be a general-purpose computer selectively activatedor reconfigured by a computer program and/or data structure stored inthe computer. The processes presented herein are not inherently relatedto any particular computer or other apparatus. In particular, variousgeneral-purpose machines may be used with programs written in accordancewith the teachings herein, or it may be more convenient to construct amore specialized apparatus to perform and/or control the required methodand processes.

As mentioned, the various stations of an integrated deposition systemmay be modular, but once connected, form a continuous system where acontrolled ambient environment is established and maintained in order toprocess substrates at the various stations within the system. FIG. 3Cdepicts integrated deposition system 300 a, which is like system 300,but in this example each of the stations is modular, specifically, an EClayer station 304 a, an IC layer station 304 b and a CE layer station306 c. In a similar embodiment, the IC layer station 304 b is omitted.Modular form is not necessary, but it is convenient, because dependingon the need, an integrated deposition system can be assembled accordingto custom needs and emerging process advancements. For example, FIG. 3Ddepicts an integrated deposition system, 300 b, with two lithiumdeposition stations, 307 a and 307 b. System 300 b is, e.g., equipped tocarry out methods herein as described above, such as the dual lithiationmethod. System 300 b could also be used to carry out a single lithiationmethod, for example by only utilizing lithium station 307 b duringprocessing of the substrate. But with modular format, e.g., if singlelithiation is the desired process, then one of the lithiation stationsis redundant and system 300 c, as depicted in FIG. 3E can be used.System 300 c has only one lithium deposition station, 307.

Systems 300 b and 300 c also have one or more TCO layer station, 308,for depositing the TCO layer on the EC stack. TCO refers to transparentconductive oxide. With reference to FIG. 1, conductive layers 104 and114 may be TCO layers. While FIGS. 3D and 3E show only a single TCOlayer station 308, it is understood that in cases where the firstconductive layer is deposited on the substrate (e.g., rather than thesubstrate being provided with the first conductive layer thereon), anadditional TCO station may be provided, for example between the entryload lock 302 and the EC layer station 306 a (or between the entry loadlock 302 and the CE layer station 306 c in cases where the counterelectrode layer is deposited prior to the electrochromic layer).Depending on the process demands, additional stations can be added tothe integrated deposition system, e.g., stations for cleaning processes,laser scribes, capping layers, etc.

The sputtering process for forming the layers (e.g., the electrochromiclayer or the counter electrode layer) may utilize one or more sputtertargets. Where one sputter target is used, the target may include all ofthe metals that are desired in the deposited layer (e.g., nickel andtungsten for a NiWO layer; nickel, tungsten, and tantalum for a NiWTaOlayer; nickel tungsten, and niobium for a NiWNbO layer; nickel, tungstenand tin for a NiWSnO layer; tungsten and molybdenum for a WMoO layer,etc.). In such cases, the target may be in the form of a metal alloy,intermetallic mixture, a metal oxide material, or a combination thereof.In cases where a metal alloy or intermetallic mixture is employed, thecomposition of the target reflects the metal ratios described herein,using the variable x, without oxygen (y is 0). For example, a metalsputter target may have a composition that is 94% (atomic) tungsten and6% (atomic) molybdenum (x=0.06). It is understood that the atomic ratioof the metal target may not translate directly to metal ratio in thesputtered tungsten molybdenum oxide, because the metals may react withoxygen at different rates, sputter from the target at different rates,and so forth. Where more than one target is used, the targets may havethe same composition or different compositions (e.g., with differentmetals or combinations of metals on each target).

The sputter target may include a grid or other overlapping shapes wheredifferent portions of the grid include the different relevant materials(e.g., certain portions of the grid may include elemental metals oralloys of metals that together form the desired composition). Forinstance, where two targets are used to form a tungsten molybdenum oxideelectrochromic layer, each target may include one or both of tungstenand molybdenum. In one example the first target includes tungsten andthe second target includes molybdenum. In certain embodiments, twotargets are used to form a nickel tungsten tantalum oxide counterelectrode. In such cases, the first target may include nickel and thesecond target may include tungsten and tantalum; or the first target mayinclude nickel and tungsten and the second target may include tantalum;or the first target may include nickel and tantalum and the secondtarget may include tungsten. Similar examples are possible with othermaterials, including but not limited to nickel tungsten tin oxide andnickel tungsten niobium oxide, each of which may be used as a counterelectrode material in certain embodiments. In any case where two or moremetals are provided together on the same target, the metals may beprovided separately (e.g., as elemental metals provided together in agrid or other pattern), as alloys, or a combination thereof.

In some cases, a sputter target may include an alloy of the relevantmaterials (e.g., tungsten and molybdenum for forming a tungstenmolybdenum oxide layer; two or more of nickel, tungsten, and tantalumfor forming a nickel tungsten tantalum oxide layer; two or more ofnickel, tungsten, and tin for forming a nickel tungsten tin oxide layer;or two or more of nickel, tungsten, and niobium for forming a nickeltungsten niobium oxide layer). Where two or more sputter targets areused, each sputter target may include at least one of the relevantmaterials (e.g., elemental and/or alloy forms of the relevant metals,any of which can be provided in oxide form). The sputter targets mayoverlap in some cases. The sputter targets may also rotate in someembodiments. As noted, the electrochromic and counter electrode layersare each typically an oxide material. Oxygen may be provided as a partof the sputter target and/or sputter gas. In certain cases, the sputtertargets are substantially pure metals or alloys (e.g., lacking oxygen),and sputtering is done in the presence of oxygen to form the oxide.

In one embodiment, in order to normalize the rate of deposition of theelectrochromic or counter electrode layer, multiple targets are used soas to obviate the need for inappropriately high power (or otherinappropriate adjustment to desired process conditions) to increasedeposition rate.

Table 2 provides various examples of sets of targets that may be usedtogether to form tungsten molybdenum oxide according to certainembodiments. Any of these materials may be provided in oxide form. Wheretwo metals are provided together, they may be provided as elementalmetals (e.g., in a grid or other pattern), or they may be provided as analloy.

TABLE 2 Composition of First Target Composition of Second TargetTungsten Molybdenum Tungsten and molybdenum —

Table 3 provides various examples of sets of targets that may be usedtogether to form nickel tungsten tantalum oxide according to certainembodiments. Any of these materials may be provided in oxide form. Wheretwo metals are provided together, they may be provided as elementalmetals (e.g., in a grid or other pattern), or they may be provided as analloy.

TABLE 3 Composition of First Composition of Second Composition of ThirdTarget Target Target Nickel and tungsten Tantalum — Nickel and tantalumTungsten — Nickel Tantalum Tungsten

Table 4 provides various examples of sets of targets that may be usedtogether to form nickel tungsten niobium oxide according to certainembodiments. Any of these materials may be provided in oxide form. Wheretwo metals are provided together, they may be provided as elementalmetals (e.g., in a grid or other pattern), or they may be provided as analloy.

TABLE 4 Composition of First Composition of Second Composition of ThirdTarget Target Target Nickel and tungsten Niobium — Nickel and niobiumTungsten — Nickel Niobium Tungsten

Table 5 provides various examples of sets of targets that may be usedtogether to form nickel tungsten tin oxide according to certainembodiments. Any of these materials may be provided in oxide form. Wheretwo metals are provided together, they may be provided as elementalmetals (e.g., in a grid or other pattern), or they may be provided as analloy.

TABLE 5 Composition of First Composition of Second Composition of ThirdTarget Target Target Nickel and tungsten Tin — Nickel and tin Tungsten —Nickel Tin Tungsten

Tables 2-5 describe various examples related to formation of tungstenmolybdenum oxide, nickel tungsten tantalum oxide, nickel tungstenniobium oxide, and nickel tungsten tin oxide. These are merely examples,and are not intended to be limiting. In other examples, differentelectrochromic and/or counter electrode materials may be used.

Various sputter target designs, orientations, and implementations arefurther discussed in U.S. Pat. No. 9,261,751, which is hereinincorporated by reference in its entirety.

The density and orientation/shape of material that sputters off of asputter target depends on various factors including, for example, themagnetic field shape and strength, pressure, and power density used togenerate the sputter plasma. The distance between adjacent targets, aswell as the distance between each target and substrate, can also affecthow the sputter plasmas will mix and how the resulting material isdeposited on the substrate.

In certain embodiments, two different types of sputter targets areprovided to deposit a single layer in an electrochromic stack: (a)primary sputter targets, which sputter material onto a substrate, and(b) secondary sputter targets, which sputter material onto the primarysputter targets. The primary and secondary sputter targets may includeany combination of metal, metal alloys, and metal oxides that achieve adesired composition in a deposited layer (including, but not limited to,any of the combinations described in Tables 2-5, with the “first target”listed in the tables corresponding to either the primary target or thesecondary target). In one particular example where the targets are usedto form tungsten molybdenum oxide, a primary sputter target includestungsten and a secondary sputter target includes molybdenum. Thesesputter targets may be used to deposit an electrochromic layercomprising tungsten molybdenum oxide. Other combinations of elementalmetals and alloys can also be used, as desired.

Where both a primary and a secondary sputter target are used, thesecondary sputter target may be operated at a potential that is cathodiccompared to the potential of the primary sputter target (which isalready cathodic). Alternatively, the targets may be operatedindependently. Still further, regardless of relative target potentials,neutral species ejected from the secondary target will deposit on theprimary target. Neutral atoms will be part of the flux, and they willdeposit on a cathodic primary target regardless of relative potentials.

It is to be understood that the configurations and/or approachesdescribed herein are exemplary in nature, and that these specificembodiments or examples are not to be considered in a limiting sense,because numerous variations are possible. The specific routines ormethods described herein may represent one or more of any number ofprocessing strategies. As such, various acts illustrated may beperformed in the sequence illustrated, in other sequences, in parallel,or in some cases omitted. Likewise, the order of the above describedprocesses may be changed. Certain references have been incorporated byreference herein. It is understood that any disclaimers or disavowalsmade in such references do not necessarily apply to the embodimentsdescribed herein. Similarly, any features described as necessary in suchreferences may be omitted in the embodiments herein.

1. An electrochromic device or an electrochromic device precursor,comprising: a first electrically conductive layer having a thicknessbetween about 10-500 nm; an electrochromic layer comprising anelectrochromic material comprising tungsten molybdenum oxide having acomposition of W_(1-x)Mo_(x)O_(y), wherein x is between about 0.05-0.30and y is between about 2.5-4.5, the electrochromic layer having athickness between about 100-500 nm; a counter electrode layer comprisinga counter electrode material comprising nickel tungsten oxide, thecounter electrode layer having a thickness between about 100-500 nm; anda second electrically conductive layer having a thickness between about100-400 nm, wherein the electrochromic layer and the counter electrodelayer are positioned between the first electrically conductive layer andthe second electrically conductive layer, and wherein the electrochromicdevice is all solid state and inorganic.
 2. The electrochromic device orelectrochromic device precursor of claim 1, wherein the electrochromiclayer is nanocrystalline.
 3. The electrochromic device or electrochromicdevice precursor of claim 1, wherein the electrochromic layer isamorphous.
 4. The electrochromic device or electrochromic deviceprecursor of claim 1, wherein the counter electrode layer isnanocrystalline.
 5. The electrochromic device or electrochromic deviceprecursor of claim 1, wherein the counter electrode layer is amorphous.6. The electrochromic device or electrochromic device precursor of claim1, wherein the counter electrode material comprises nickel tungstentantalum oxide.
 7. The electrochromic device or electrochromic deviceprecursor of claim 1, wherein the counter electrode material comprisesnickel tungsten niobium oxide.
 8. The electrochromic device orelectrochromic device precursor of claim 1, wherein the counterelectrode material comprises nickel tungsten tin oxide.
 9. Theelectrochromic device or electrochromic device precursor of claim 1,wherein the electrochromic layer, the counter electrode layer, and thesecond electrically conductive layer were all formed through sputtering.10. The electrochromic device or electrochromic device precursor ofclaim 1, wherein the electrochromic device or electrochromic deviceprecursor does not include a homogenous layer of ion conducting,electronically insulating material between the electrochromic layer andthe counter electrode layer.
 11. The electrochromic device orelectrochromic device precursor of claim 1, wherein the electrochromicmaterial is in physical contact with the counter electrode material. 12.The electrochromic device or electrochromic device precursor of claim 1,wherein at least one of the electrochromic layer and the counterelectrode layer comprise two or more layers or portions, one of thelayers or the portions being superstoichiometric with respect to oxygen.13. The electrochromic device or electrochromic device precursor ofclaim 12, wherein either: (a) the electrochromic layer comprises the twoor more layers, and the layer that is superstoichiometric with respectto oxygen being in contact with the counter electrode layer, or (b) thecounter electrode layer comprises the two or more layers, and the layerthat is superstoichiometric with respect to oxygen being in contact withthe electrochromic layer.
 14. The electrochromic device orelectrochromic device precursor of claim 12, wherein either: (a) theelectrochromic layer comprises the two or more layers or portions, thetwo or more layers or portions together forming the electrochromic layeras a graded composition layer, and the layer or portion of theelectrochromic layer that is superstoichiometric with respect to oxygenbeing in contact with the counter electrode layer, or (b) the counterelectrode layer comprises the two or more layers or portions, the two ormore layers or portions together forming the counter electrode layer asa graded composition layer, and the layer or portion of the counterelectrode layer that is superstoichiometric with respect to oxygen beingin contact with the electrochromic layer.
 15. The electrochromic deviceor electrochromic device precursor of claim 1, further comprising amaterial that is ion conducting and substantially electronicallyinsulating that is formed in situ at an interface between theelectrochromic layer and the counter electrode layer.
 16. Theelectrochromic device or electrochromic device precursor of claim 1,further comprising an ion conducting layer comprising a materialselected from the group consisting of: lithium silicate, lithiumaluminum silicate, lithium oxide, lithium tungstate, lithium aluminumborate, lithium borate, lithium zirconium silicate, lithium niobate,lithium borosilicate, lithium phosphosilicate, lithium nitride, lithiumoxynitride, lithium aluminum fluoride, lithium phosphorus oxynitride(LiPON), lithium lanthanum titanate (LLT), lithium tantalum oxide,lithium zirconium oxide, lithium silicon carbon oxynitride (LiSiCON),lithium phosphate, lithium titanium phosphate, lithium germaniumvanadium oxide, lithium zinc germanium oxide, and combinations thereof.17. The electrochromic device or electrochromic device precursor ofclaim 16, wherein the ion conducting layer has a thickness between about5-100 nm.
 18. The electrochromic device or electrochromic deviceprecursor of claim 16, wherein the ion conducting layer comprises amaterial selected from the group consisting of: lithium silicate,lithium aluminum silicate, lithium zirconium silicate, lithiumborosilicate, lithium phosphosilicate, lithium phosphorus oxynitride(LiPON), lithium silicon carbon oxynitride (LiSiCON), and combinationsthereof.
 19. The electrochromic device or electrochromic deviceprecursor of claim 1, wherein x is between about 0.1 and 0.25.
 20. Theelectrochromic device or electrochromic device precursor of claim 1,wherein x is between about 0.15 and 0.2.
 21. The electrochromic deviceor electrochromic device precursor of claim 12, wherein the layer orportion that is superstoichiometric with respect to oxygen has an excessof oxygen.
 22. The electrochromic device or electrochromic deviceprecursor of claim 1, further comprising an intermediate layerpositioned between the electrochromic layer and the counter electrodelayer, wherein the intermediate layer comprises a tungsten oxide that issuperstoichiometric with respect to oxygen.
 23. The electrochromicdevice or electrochromic device precursor of claim 22, wherein thetungsten oxide does not contain molybdenum.
 24. The electrochromicdevice or electrochromic device precursor of claim 22, wherein thetungsten oxide comprises molybdenum.
 25. The electrochromic device orelectrochromic device precursor of claim 22, wherein the tungsten oxidedoes not comprise molybdenum and is amorphous.
 26. The electrochromicdevice or electrochromic device precursor of claim 1, wherein thecounter electrode layer comprises a first sublayer and a secondsublayer, wherein the first sublayer comprises a first composition ofnickel tungsten oxide and the second sublayer comprise a secondcomposition of nickel tungsten oxide, wherein the first composition andsecond composition are different from one another. 27.-47. (canceled)